Get Image dimensions using Javascript during file upload - asp.net

I have file upload UI element in which the user will upload images. Here I have to validate the height and width of the image in client side. Is it possible to find the size of the image having only the file path in JS?
Note: If No, is there any other way to find the dimensions in Client side?

You can do this on browsers that support the new File API from the W3C, using the readAsDataURL function on the FileReader interface and assigning the data URL to the src of an img (after which you can read the height and width of the image). Currently Firefox 3.6 supports the File API, and I think Chrome and Safari either already do or are about to.
So your logic during the transitional phase would be something like this:
Detect whether the browser supports the File API (which is easy: if (typeof window.FileReader === 'function')).
If it does, great, read the data locally and insert it in an image to find the dimensions.
If not, upload the file to the server (probably submitting the form from an iframe to avoid leaving the page), and then poll the server asking how big the image is (or just asking for the uploaded image, if you prefer).
Edit I've been meaning to work up an example of the File API for some time; here's one:
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-type" content="text/html;charset=UTF-8">
<title>Show Image Dimensions Locally</title>
<style type='text/css'>
body {
font-family: sans-serif;
}
</style>
<script type='text/javascript'>
function loadImage() {
var input, file, fr, img;
if (typeof window.FileReader !== 'function') {
write("The file API isn't supported on this browser yet.");
return;
}
input = document.getElementById('imgfile');
if (!input) {
write("Um, couldn't find the imgfile element.");
}
else if (!input.files) {
write("This browser doesn't seem to support the `files` property of file inputs.");
}
else if (!input.files[0]) {
write("Please select a file before clicking 'Load'");
}
else {
file = input.files[0];
fr = new FileReader();
fr.onload = createImage;
fr.readAsDataURL(file);
}
function createImage() {
img = document.createElement('img');
img.onload = imageLoaded;
img.style.display = 'none'; // If you don't want it showing
img.src = fr.result;
document.body.appendChild(img);
}
function imageLoaded() {
write(img.width + "x" + img.height);
// This next bit removes the image, which is obviously optional -- perhaps you want
// to do something with it!
img.parentNode.removeChild(img);
img = undefined;
}
function write(msg) {
var p = document.createElement('p');
p.innerHTML = msg;
document.body.appendChild(p);
}
}
</script>
</head>
<body>
<form action='#' onsubmit="return false;">
<input type='file' id='imgfile'>
<input type='button' id='btnLoad' value='Load' onclick='loadImage();'>
</form>
</body>
</html>
Works great on Firefox 3.6. I avoided using any library there, so apologies for the attribute (DOM0) style event handlers and such.

The previous example is Okay, but it is far from perfect.
var reader = new FileReader();
reader.onload = function(e)
{
var image = new Image();
image.onload = function()
{
console.log(this.width, this.height);
};
image.src = e.target.result;
};
reader.readAsDataURL(this.files[0]);

If you use a flash based uploaded such as SWFUpload you can have all the info you want as well as multiple queued uploads.
I recommend SWFUpload and am in no way associated with them other than as a user.
You could also write a silverlight control to pick your file and upload it.

No, You can't, filename and file content are send to the server in http headerbody, javascript cannot manipulate those fields.

HTML5 is definitely the correct solution here.
You should always code for the future, not the past.
The best way to deal with HTML4 browsers is to either fall back on degraded functionality or use Flash (but only if the browser does not support the HTML5 file API)
Using the img.onload event will enable you to recover the dimensions of the file.
Its working for an app I'm working on.

Related

css not overriding external css? [duplicate]

I have a simple page that has some iframe sections (to display RSS links). How can I apply the same CSS format from the main page to the page displayed in the iframe?
Edit: This does not work cross domain unless the appropriate CORS header is set.
There are two different things here: the style of the iframe block and the style of the page embedded in the iframe. You can set the style of the iframe block the usual way:
<iframe name="iframe1" id="iframe1" src="empty.htm"
frameborder="0" border="0" cellspacing="0"
style="border-style: none;width: 100%; height: 120px;"></iframe>
The style of the page embedded in the iframe must be either set by including it in the child page:
<link type="text/css" rel="Stylesheet" href="Style/simple.css" />
Or it can be loaded from the parent page with Javascript:
var cssLink = document.createElement("link");
cssLink.href = "style.css";
cssLink.rel = "stylesheet";
cssLink.type = "text/css";
frames['iframe1'].document.head.appendChild(cssLink);
I met this issue with Google Calendar. I wanted to style it on a darker background and change font.
Luckily, the URL from the embed code had no restriction on direct access, so by using PHP function file_get_contents it is possible to get the
entire content from the page. Instead of calling the Google URL, it is possible to call a php file located on your server, ex. google.php, which will contain the original content with modifications:
$content = file_get_contents('https://www.google.com/calendar/embed?src=%23contacts%40group.v.calendar.google.com&ctz=America/Montreal');
Adding the path to your stylesheet:
$content = str_replace('</head>','<link rel="stylesheet" href="http://www.yourwebsiteurl.com/google.css" /></head>', $content);
(This will place your stylesheet last just before the head end tag.)
Specify the base url form the original url in case css and js are called relatively:
$content = str_replace('</title>','</title><base href="https://www.google.com/calendar/" />', $content);
The final google.php file should look like this:
<?php
$content = file_get_contents('https://www.google.com/calendar/embed?src=%23contacts%40group.v.calendar.google.com&ctz=America/Montreal');
$content = str_replace('</title>','</title><base href="https://www.google.com/calendar/" />', $content);
$content = str_replace('</head>','<link rel="stylesheet" href="http://www.yourwebsiteurl.com/google.css" /></head>', $content);
echo $content;
Then you change the iframe embed code to:
<iframe src="http://www.yourwebsiteurl.com/google.php" style="border: 0" width="800" height="600" frameborder="0" scrolling="no"></iframe>
Good luck!
If the content of the iframe is not completely under your control or you want to access the content from different pages with different styles you could try manipulating it using JavaScript.
var frm = frames['frame'].document;
var otherhead = frm.getElementsByTagName("head")[0];
var link = frm.createElement("link");
link.setAttribute("rel", "stylesheet");
link.setAttribute("type", "text/css");
link.setAttribute("href", "style.css");
otherhead.appendChild(link);
Note that depending on what browser you use this might only work on pages served from the same domain.
var $head = $("#eFormIFrame").contents().find("head");
$head.append($("<link/>", {
rel: "stylesheet",
href: url,
type: "text/css"
}));
Here is how to apply CSS code directly without using <link> to load an extra stylesheet.
var head = jQuery("#iframe").contents().find("head");
var css = '<style type="text/css">' +
'#banner{display:none}; ' +
'</style>';
jQuery(head).append(css);
This hides the banner in the iframe page. Thank you for your suggestions!
If you control the page in the iframe, as hangy said, the easiest approach is to create a shared CSS file with common styles, then just link to it from your html pages.
Otherwise it is unlikely you will be able to dynamically change the style of a page from an external page in your iframe. This is because browsers have tightened the security on cross frame dom scripting due to possible misuse for spoofing and other hacks.
This tutorial may provide you with more information on scripting iframes in general. About cross frame scripting explains the security restrictions from the IE perspective.
An iframe is universally handled like a different HTML page by most browsers. If you want to apply the same stylesheet to the content of the iframe, just reference it from the pages used in there.
The above with a little change works:
var cssLink = document.createElement("link")
cssLink.href = "pFstylesEditor.css";
cssLink.rel = "stylesheet";
cssLink.type = "text/css";
//Instead of this
//frames['frame1'].document.body.appendChild(cssLink);
//Do this
var doc=document.getElementById("edit").contentWindow.document;
//If you are doing any dynamic writing do that first
doc.open();
doc.write(myData);
doc.close();
//Then append child
doc.body.appendChild(cssLink);
Works fine with ff3 and ie8 at least
The following worked for me.
var iframe = top.frames[name].document;
var css = '' +
'<style type="text/css">' +
'body{margin:0;padding:0;background:transparent}' +
'</style>';
iframe.open();
iframe.write(css);
iframe.close();
Expanding on the above jQuery solution to cope with any delays in loading the frame contents.
$('iframe').each(function(){
function injectCSS(){
$iframe.contents().find('head').append(
$('<link/>', { rel: 'stylesheet', href: 'iframe.css', type: 'text/css' })
);
}
var $iframe = $(this);
$iframe.on('load', injectCSS);
injectCSS();
});
use can try this:
$('iframe').load( function() {
$('iframe').contents().find("head")
.append($("<style type='text/css'> .my-class{display:none;} </style>"));
});
If you want to reuse CSS and JavaScript from the main page maybe you should consider replacing <IFRAME> with a Ajax loaded content. This is more SEO friendly now when search bots are able to execute JavaScript.
This is jQuery example that includes another html page into your document. This is much more SEO friendly than iframe. In order to be sure that the bots are not indexing the included page just add it to disallow in robots.txt
<html>
<header>
<script src="/js/jquery.js" type="text/javascript"></script>
</header>
<body>
<div id='include-from-outside'></div>
<script type='text/javascript'>
$('#include-from-outside').load('http://example.com/included.html');
</script>
</body>
</html>
You could also include jQuery directly from Google: http://code.google.com/apis/ajaxlibs/documentation/ - this means optional auto-inclusion of newer versions and some significant speed increase. Also, means that you have to trust them for delivering you just the jQuery ;)
My compact version:
<script type="text/javascript">
$(window).load(function () {
var frame = $('iframe').get(0);
if (frame != null) {
var frmHead = $(frame).contents().find('head');
if (frmHead != null) {
frmHead.append($('style, link[rel=stylesheet]').clone()); // clone existing css link
//frmHead.append($("<link/>", { rel: "stylesheet", href: "/styles/style.css", type: "text/css" })); // or create css link yourself
}
}
});
</script>
However, sometimes the iframe is not ready on window loaded, so there is a need of using a timer.
Ready-to-use code (with timer):
<script type="text/javascript">
var frameListener;
$(window).load(function () {
frameListener = setInterval("frameLoaded()", 50);
});
function frameLoaded() {
var frame = $('iframe').get(0);
if (frame != null) {
var frmHead = $(frame).contents().find('head');
if (frmHead != null) {
clearInterval(frameListener); // stop the listener
frmHead.append($('style, link[rel=stylesheet]').clone()); // clone existing css link
//frmHead.append($("<link/>", { rel: "stylesheet", href: "/styles/style.css", type: "text/css" })); // or create css link yourself
}
}
}
</script>
...and jQuery link:
<script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.9.1.min.js" type="text/javascript"></script>
As many answers are written for the same domains, I'll write how to do this in cross domains.
First, you need to know the Post Message API. We need a messenger to communicate between two windows.
Here's a messenger I created.
/**
* Creates a messenger between two windows
* which have two different domains
*/
class CrossMessenger {
/**
*
* #param {object} otherWindow - window object of the other
* #param {string} targetDomain - domain of the other window
* #param {object} eventHandlers - all the event names and handlers
*/
constructor(otherWindow, targetDomain, eventHandlers = {}) {
this.otherWindow = otherWindow;
this.targetDomain = targetDomain;
this.eventHandlers = eventHandlers;
window.addEventListener("message", (e) => this.receive.call(this, e));
}
post(event, data) {
try {
// data obj should have event name
var json = JSON.stringify({
event,
data
});
this.otherWindow.postMessage(json, this.targetDomain);
} catch (e) {}
}
receive(e) {
var json;
try {
json = JSON.parse(e.data ? e.data : "{}");
} catch (e) {
return;
}
var eventName = json.event,
data = json.data;
if (e.origin !== this.targetDomain)
return;
if (typeof this.eventHandlers[eventName] === "function")
this.eventHandlers[eventName](data);
}
}
Using this in two windows to communicate can solve your problem.
In the main windows,
var msger = new CrossMessenger(iframe.contentWindow, "https://iframe.s.domain");
var cssContent = Array.prototype.map.call(yourCSSElement.sheet.cssRules, css_text).join('\n');
msger.post("cssContent", {
css: cssContent
})
Then, receive the event from the Iframe.
In the Iframe:
var msger = new CrossMessenger(window.parent, "https://parent.window.domain", {
cssContent: (data) => {
var cssElem = document.createElement("style");
cssElem.innerHTML = data.css;
document.head.appendChild(cssElem);
}
})
See the Complete Javascript and Iframes tutorial for more details.
Other answers here seem to use jQuery and CSS links.
This code uses vanilla JavaScript. It creates a new <style> element. It sets the text content of that element to be a string containing the new CSS. And it appends that element directly to the iframe document's head.
var iframe = document.getElementById('the-iframe');
var style = document.createElement('style');
style.textContent =
'.some-class-name {' +
' some-style-name: some-value;' +
'}'
;
iframe.contentDocument.head.appendChild(style);
When you say "doc.open()" it means you can write whatever HTML tag inside the iframe, so you should write all the basic tags for the HTML page and if you want to have a CSS link in your iframe head just write an iframe with CSS link in it. I give you an example:
doc.open();
doc.write('<!DOCTYPE html><html><head><meta charset="utf-8"/><meta http-quiv="Content-Type" content="text/html; charset=utf-8"/><title>Print Frame</title><link rel="stylesheet" type="text/css" href="/css/print.css"/></head><body><table id="' + gridId + 'Printable' + '" class="print" >' + out + '</table></body></html>');
doc.close();
You will not be able to style the contents of the iframe this way. My suggestion would be to use serverside scripting (PHP, ASP, or a Perl script) or find an online service that will convert a feed to JavaScript code. The only other way to do it would be if you can do a serverside include.
Incase if you have access to iframe page and want a different CSS to apply on it only when you load it via iframe on your page, here I found a solution for these kind of things
this works even if iframe is loading a different domain
check about postMessage()
plan is, send the css to iframe as a message like
iframenode.postMessage('h2{color:red;}','*');
* is to send this message irrespective of what domain it is in iframe
and receive the message in iframe and add the received message(CSS) to that document head.
code to add in iframe page
window.addEventListener('message',function(e){
if(e.data == 'send_user_details')
document.head.appendChild('<style>'+e.data+'</style>');
});
I think the easiest way is to add another div, in the same place as the iframe, then
make its z-index bigger than the iframe container, so you can easly just style your own div. If you need to click on it, just use pointer-events:none on your own div, so the iframe would be working in case you need to click on it ;)
I hope It will help someone ;)
I found another solution to put the style in the main html like this
<style id="iframestyle">
html {
color: white;
background: black;
}
</style>
<style>
html {
color: initial;
background: initial;
}
iframe {
border: none;
}
</style>
and then in iframe do this (see the js onload)
<iframe onload="iframe.document.head.appendChild(ifstyle)" name="log" src="/upgrading.log"></iframe>
and in js
<script>
ifstyle = document.getElementById('iframestyle')
iframe = top.frames["log"];
</script>
It may not be the best solution, and it certainly can be improved, but it is another option if you want to keep a "style" tag in parent window
Here, There are two things inside the domain
iFrame Section
Page Loaded inside the iFrame
So you want to style those two sections as follows,
1. Style for the iFrame Section
It can style using CSS with that respected id or class name. You can just style it in your parent Style sheets also.
<style>
#my_iFrame{
height: 300px;
width: 100%;
position:absolute;
top:0;
left:0;
border: 1px black solid;
}
</style>
<iframe name='iframe1' id="my_iFrame" src="#" cellspacing="0"></iframe>
2. Style the Page Loaded inside the iFrame
This Styles can be loaded from the parent page with the help of Javascript
var cssFile = document.createElement("link")
cssFile.rel = "stylesheet";
cssFile.type = "text/css";
cssFile.href = "iFramePage.css";
then set that CSS file to the respected iFrame section
//to Load in the Body Part
frames['my_iFrame'].document.body.appendChild(cssFile);
//to Load in the Head Part
frames['my_iFrame'].document.head.appendChild(cssFile);
Here, You can edit the Head Part of the Page inside the iFrame using this way also
var $iFrameHead = $("#my_iFrame").contents().find("head");
$iFrameHead.append(
$("<link/>",{
rel: "stylesheet",
href: urlPath,
type: "text/css" }
));
We can insert style tag into iframe.
<style type="text/css" id="cssID">
.className
{
background-color: red;
}
</style>
<iframe id="iFrameID"></iframe>
<script type="text/javascript">
$(function () {
$("#iFrameID").contents().find("head")[0].appendChild(cssID);
//Or $("#iFrameID").contents().find("head")[0].appendChild($('#cssID')[0]);
});
</script>
var link1 = document.createElement('link');
link1.type = 'text/css';
link1.rel = 'stylesheet';
link1.href = "../../assets/css/normalize.css";
window.frames['richTextField'].document.body.appendChild(link1);
This is how I'm doing in production. It's worth bearing in mind that if the iframe belongs to other website, it will trigger the CORS error and will not work.
var $iframe = document.querySelector(`iframe`);
var doc = $iframe.contentDocument;
var style = doc.createElement("style");
style.textContent = `*{display:none!important;}`;
doc.head.append(style);
In some cases you may also want to attach a load event to the iframe:
var $iframe = document.querySelector(`iframe`);
$iframe.addEventListener("load", function() {
var doc = $iframe.contentDocument;
var style = doc.createElement("style");
style.textContent = `*{display:none!important;}`;
doc.head.append(style);
});
There is a wonderful script that replaces a node with an iframe version of itself.
CodePen Demo
Usage Examples:
// Single node
var component = document.querySelector('.component');
var iframe = iframify(component);
// Collection of nodes
var components = document.querySelectorAll('.component');
var iframes = Array.prototype.map.call(components, function (component) {
return iframify(component, {});
});
// With options
var component = document.querySelector('.component');
var iframe = iframify(component, {
headExtra: '<style>.component { color: red; }</style>',
metaViewport: '<meta name="viewport" content="width=device-width">'
});
As an alternative, you can use CSS-in-JS technology, like below lib:
https://github.com/cssobj/cssobj
It can inject JS object as CSS to iframe, dynamically
This is just a concept, but don't implement this without security checks and filtering! Otherwise script could hack your site!
Answer: if you control target site, you can setup the receiver script like:
1) set the iframe link with style parameter, like:
http://your_site.com/target.php?color=red
(the last phrase is a{color:red} encoded by urlencode function.
2) set the receiver page target.php like this:
<head>
..........
$col = FILTER_VAR(SANITIZE_STRING, $_GET['color']);
<style>.xyz{color: <?php echo (in_array( $col, ['red','yellow','green'])? $col : "black") ;?> } </style>
..........
Well, I have followed these steps:
Div with a class to hold iframe
Add iframe to the div.
In CSS file,
divClass { width: 500px; height: 500px; }
divClass iframe { width: 100%; height: 100%; }
This works in IE 6. Should work in other browsers, do check!

Pop up window not appending text

I am trying to implement a 'Trace Window' pop up window when I enter a website, and then send messages to that window throughout the website in Order to diagnose some of the more awkward issues i have with the site.
The Problem is that the page changes, if The trace window already exists, all content is removed, before the new TraceText is added.
What I want is a Window that can be sent messages from any page inside the website.
I have a javascript Script debugger.js which I include as a script in every screen (shown below) I would then call the sendToTraceWindow() function to send a message to it thoughout the website. this is currently Mostly done in vbscript at present, due to the issues i am currenctly investigating.
I think it is because i am scripting in the debugger.js into every screen, which sets the traceWindow variable = null (see code below) but I do not know how to get around this!
Any help much appreciated.
Andrew
code examples:
debugger.js:
var traceWindow = null
function opentraceWindow()
{
traceWindow = window.open('traceWindow.asp','traceWindow','width=400,height=800')
}
function sendToTracewindow(sCaller, pMessage)
{
try
{
if (!traceWindow)
{
opentraceWindow()
}
if (!traceWindow.closed)
{
var currentTrace = traceWindow.document.getElementById('trace').value
var newTrace = sCaller + ":" + pMessage + "\n" + currentTrace
traceWindow.document.getElementById('trace').value = newTrace
}
}
catch(e)
{
var currentTrace = traceWindow.document.getElementById('trace').value
var newTrace = "error tracing:" + e.message + "\n" + currentTrace
traceWindow.document.getElementById('trace').value = newTrace
}
}
traceWindow.asp - just a textarea with id='trace':
<HTML>
<head>
<title>Debug Window</title>
</head>
<body>
<textarea id="trace" rows="50" cols="50"></textarea>
</body>
</HTML>
I don't think there is any way around the fact that your traceWindow variable will be reset on every page load, therefore rendering your handle to the existing window invalid. However, if you don't mind leveraging LocalStorage and some jQuery, I believe you can achieve the functionality you are looking for.
Change your trace window to this:
<html>
<head>
<title>Debug Window</title>
<script type="text/javascript" src="YOUR_PATH_TO/jQuery.js" />
<script type="text/javascript" src="YOUR_PATH_TO/jStorage.js" />
<script type="text/javascript" src="YOUR_PATH_TO/jquery.json-2.2.js" />
<script type="text/javascript">
var traceOutput;
var traceLines = [];
var localStorageKey = "traceStorage";
$(function() {
// document.ready.
// Assign the trace textarea to the global handle.
traceOutput = $("#trace");
// load any cached trace lines from local storage
if($.jStorage.get(localStorageKey, null) != null) {
// fill the lines array
traceLines = $.jStorage.get(localStorageKey);
// populate the textarea
traceOutput.val(traceLines.join("\n"));
}
});
function AddToTrace(data) {
// append the new trace data to the textarea with a line break.
traceOutput.val(traceOutput.val() + "\n" + data);
// add the data to the lines array
traceLines[tracelines.length] = data;
// save to local storage
$.jStorage.set(localStorageKey, traceLines);
}
function ClearTrace() {
// empty the textarea
traceOutput.val("");
// clear local storage
$.jStorage.deleteKey(localStorageKey);
}
</script>
</head>
<body>
<textarea id="trace" rows="50" cols="50"></textarea>
</body>
</html>
Then, in your pages where you want to trace data, you could modify your javascript like so:
var traceWindow = null;
function opentraceWindow() {
traceWindow = window.open('traceWindow.asp','traceWindow','width=400,height=800');
}
function sendToTracewindow(sCaller, pMessage) {
traceWindow.AddToTrace(sCaller + ":" + pMessage);
}
Every time a new page is loaded and the trace window is refreshed, the existing trace data is loaded from local storage and displayed in your textarea. This should achieve the functionality that you are looking for.
Please be kind on any errors - I'm winging this on a Monday morning!
Finding the jQuery library should be trivial. You can find the jStorage library here: http://www.jstorage.info/, and you can find jquery-json here: http://code.google.com/p/jquery-json/

Image load timeout in Internet Explorer

I have a page for an internal app that displays document images streamed from a document storage system using a web service. The problem I am having is that when a user does their search they may get hundreds of hits, which I have to display on one large page so they can print them all. This works fine in Firefox, but in IE it stops loading the images after a while so I get a hundred or so displayed and the rest just have the broken image symbol. Is there a setting somewhere that I can change this timeout?
If the issue is indeed a timeout, you might be able to work around it by using a "lazy load" script and adding new images to the document only after existing images have loaded.
There are a lot of ways to do this, but here's a simple example I threw together and tested. Instead of this:
<img src="image001.jpg" />
<img src="image002.jpg" />
<img src="image003.jpg" />
<img src="image004.jpg" />
<!-- Etc etc etc -->
You could do this:
<div id="imgsGoHere">
</div>
<script type="text/javascript">
function crossBrowserEventAttach(objectRef, eventName, functionRef)
{
try {
objectRef.addEventListener(eventName, functionRef, false);
}
catch(err) {
try {
objectRef.attachEvent("on" + eventName, functionRef);
}
catch(err2) {
// event attachment failed
}
}
}
function addImageToPage()
{
var newImageElement = document.createElement("img");
newImageElement.src = imageArray[nextImageNumber];
var targetElement = document.getElementById("imgsGoHere");
targetElement.appendChild(newImageElement);
nextImageNumber++;
if (nextImageNumber < imageArray.length) {
crossBrowserEventAttach(newImageElement, "load", addImageToPage);
crossBrowserEventAttach(newImageElement, "error", addImageToPage);
}
}
var nextImageNumber = 0;
var imageArray = new Array();
imageArray[imageArray.length] = "image001.jpg";
imageArray[imageArray.length] = "image002.jpg";
imageArray[imageArray.length] = "image003.jpg";
// .
// .
// .
// Snip hundreds of rows
// .
// .
// .
imageArray[imageArray.length] = "image999.jpg";
addImageToPage();
</script>
Each image is added to the page only after the previous image loads (or fails to load). If your browser is timing out, I think that will fix it.
Of course, the problem might actually not be a timeout, but rather that you're running out of memory/system resources and IE is giving up. Or there might be an IE DOM limitation like Sra said.
No final solution, but some hints...
I think the ie Dom hangs up. I,ve seen this in other cases. I needed simply to show the images and used a js which loads the image the time they came into focus, but that want work if you directly hit print I think. Can you use the new css ability to store imagedata directly instead of links. That should solve your problem. I am not quite sure but I think it is supported since ie 7
My guess is that you have to work around the IE setting, the easiest way to do it is simply not showing images that are not loaded or replacing them with a default image:
your html:
<img src="http://domain.com/image.jpg" />
your js:
$('img').load(function(){
// ... loaded
}).error(function(){
// ... not loaded, replace
$(this).attr('src','/whatever/default.jpg');
// ... not loaded, hide
$(this).hide();
});
That is a problem with microsoft. Unfortunately, this is a setting that would have to be changed on every single computer, as there is no remote way to alter it. To change it on your computer, try opening regedit and adding the RecieveTimeout DWORD with a Value of (#of minutes)*6000. Hope this helps-CodeKid1001
Edit: Sorry about that, I forgot to put in the file path:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\InternetSettings
I used something similar to laod HD pictures as a background using ASP Pages
But i used jQuery to handle the images and its loading. This is a sample for 1 image but with a bit of tweaking you can load dynamically
myImage = new Image();
$(myImage).load(function ()
{
$(this).hide(); //Stops the loading effect of large images. can be removed
$('.csBackground li').append(this); //Append image to where you need it
$(myImage).show();
}).attr('src', settings.images[0]) //I pass an array from ASP code behind so 0 can be 'i'
.error( function { checkImages(); } ) //try and relaod the image or something?
So instead of changing the timeout- just try and reload the images on error.
Otherwise i only found a solution that is client specific (HTTP Timeout)
http://support.microsoft.com/kb/813827

Is there a cross-domain iframe height auto-resizer that works?

I tried a few solutions but wasn't successful. I'm wondering if there is a solution out there preferably with an easy-to-follow tutorial.
You have three alternatives:
1. Use iFrame-resizer
This is a simple library for keeping iFrames sized to their content. It uses the PostMessage and MutationObserver APIs, with fall backs for IE8-10. It also has options for the content page to request the containing iFrame is a certain size and can also close the iFrame when your done with it.
https://github.com/davidjbradshaw/iframe-resizer
2. Use Easy XDM (PostMessage + Flash combo)
Easy XDM uses a collection of tricks for enabling cross-domain communication between different windows in a number of browsers, and there are examples for using it for iframe resizing:
http://easyxdm.net/wp/2010/03/17/resize-iframe-based-on-content/
http://kinsey.no/blog/index.php/2010/02/19/resizing-iframes-using-easyxdm/
Easy XDM works by using PostMessage on modern browsers and a Flash based solution as fallback for older browsers.
See also this thread on Stackoverflow (there are also others, this is a commonly asked question). Also, Facebook would seem to use a similar approach.
3. Communicate via a server
Another option would be to send the iframe height to your server and then poll from that server from the parent web page with JSONP (or use a long poll if possible).
I got the solution for setting the height of the iframe dynamically based on it's content. This works for the cross domain content.
There are some steps to follow to achieve this.
Suppose you have added iframe in "abc.com/page" web page
<div>
<iframe id="IframeId" src="http://xyz.pqr/contactpage" style="width:100%;" onload="setIframeHeight(this)"></iframe>
</div>
Next you have to bind windows "message" event under web page "abc.com/page"
window.addEventListener('message', function (event) {
//Here We have to check content of the message event for safety purpose
//event data contains message sent from page added in iframe as shown in step 3
if (event.data.hasOwnProperty("FrameHeight")) {
//Set height of the Iframe
$("#IframeId").css("height", event.data.FrameHeight);
}
});
On iframe load you have to send message to iframe window content with "FrameHeight" message:
function setIframeHeight(ifrm) {
var height = ifrm.contentWindow.postMessage("FrameHeight", "*");
}
On main page that added under iframe here "xyz.pqr/contactpage" you have to bind windows "message" event where all messages are going to receive from parent window of "abc.com/page"
window.addEventListener('message', function (event) {
// Need to check for safety as we are going to process only our messages
// So Check whether event with data(which contains any object) contains our message here its "FrameHeight"
if (event.data == "FrameHeight") {
//event.source contains parent page window object
//which we are going to use to send message back to main page here "abc.com/page"
//parentSourceWindow = event.source;
//Calculate the maximum height of the page
var body = document.body, html = document.documentElement;
var height = Math.max(body.scrollHeight, body.offsetHeight,
html.clientHeight, html.scrollHeight, html.offsetHeight);
// Send height back to parent page "abc.com/page"
event.source.postMessage({ "FrameHeight": height }, "*");
}
});
What I did was compare the iframe scrollWidth until it changed size while i incrementally set the IFrame Height. And it worked fine for me. You can adjust the increment to whatever is desired.
<script type="text/javascript">
function AdjustIFrame(id) {
var frame = document.getElementById(id);
var maxW = frame.scrollWidth;
var minW = maxW;
var FrameH = 100; //IFrame starting height
frame.style.height = FrameH + "px"
while (minW == maxW) {
FrameH = FrameH + 100; //Increment
frame.style.height = FrameH + "px";
minW = frame.scrollWidth;
}
}
</script>
<iframe id="RefFrame" onload="AdjustIFrame('RefFrame');" class="RefFrame"
src="http://www.YourUrl.com"></iframe>
I have a script that drops in the iframe with it's content. It also makes sure that iFrameResizer exists (it injects it as a script) and then does the resizing.
I'll drop in a simplified example below.
// /js/embed-iframe-content.js
(function(){
// Note the id, we need to set this correctly on the script tag responsible for
// requesting this file.
var me = document.getElementById('my-iframe-content-loader-script-tag');
function loadIFrame() {
var ifrm = document.createElement('iframe');
ifrm.id = 'my-iframe-identifier';
ifrm.setAttribute('src', 'http://www.google.com');
ifrm.style.width = '100%';
ifrm.style.border = 0;
// we initially hide the iframe to avoid seeing the iframe resizing
ifrm.style.opacity = 0;
ifrm.onload = function () {
// this will resize our iframe
iFrameResize({ log: true }, '#my-iframe-identifier');
// make our iframe visible
ifrm.style.opacity = 1;
};
me.insertAdjacentElement('afterend', ifrm);
}
if (!window.iFrameResize) {
// We first need to ensure we inject the js required to resize our iframe.
var resizerScriptTag = document.createElement('script');
resizerScriptTag.type = 'text/javascript';
// IMPORTANT: insert the script tag before attaching the onload and setting the src.
me.insertAdjacentElement('afterend', ifrm);
// IMPORTANT: attach the onload before setting the src.
resizerScriptTag.onload = loadIFrame;
// This a CDN resource to get the iFrameResizer code.
// NOTE: You must have the below "coupled" script hosted by the content that
// is loaded within the iframe:
// https://unpkg.com/iframe-resizer#3.5.14/js/iframeResizer.contentWindow.min.js
resizerScriptTag.src = 'https://unpkg.com/iframe-resizer#3.5.14/js/iframeResizer.min.js';
} else {
// Cool, the iFrameResizer exists so we can just load our iframe.
loadIFrame();
}
}())
Then the iframe content can be injected anywhere within another page/site by using the script like so:
<script
id="my-iframe-content-loader-script-tag"
type="text/javascript"
src="/js/embed-iframe-content.js"
></script>
The iframe content will be injected below wherever you place the script tag.
Hope this is helpful to someone. 👍
I ran into this issue while working on something at work (using React). Basically, we have some external html content that we save into our document table in the database and then insert onto the page under certain circumstances when you're in the Documents dataset.
So, given n inlines, of which up to n could contain external html, we needed to devise a system to automatically resize the iframe of each inline once the content fully loaded in each. After spinning my wheels for a bit, this is how I ended up doing it:
Set a message event listener in the index of our React app which checks for a a specific key that we will set from the sender iframe.
In the component that actually renders the iframes, after inserting the external html into it, I append a <script> tag that will wait for the iframe's window.onload to fire. Once that fires, we use postMessage to send a message to the parent window with information about the iframe id, computed height, etc.
If the origin matches and the key is satisfied in the index listener, grab the DOM id of the iframe that we pass in the MessageEvent object
Once we have the iframe, just set the height from the value that is passed from the iframe postMessage.
// index
if (window.postMessage) {
window.addEventListener("message", (messageEvent) => {
if (
messageEvent.data.origin &&
messageEvent.data.origin === "company-name-iframe"
) {
const iframe = document.getElementById(messageEvent.data.id)
// this is the only way to ensure that the height of the iframe container matches its body height
iframe.style.height = `${messageEvent.data.height}px`
// by default, the iframe will not expand to fill the width of its parent
iframe.style.width = "100%"
// the iframe should take precedence over all pointer events of its immediate parent
// (you can still click around the iframe to segue, for example, but all content of the iframe
// will act like it has been directly inserted into the DOM)
iframe.style.pointerEvents = "all"
// by default, iframes have an ugly web-1.0 border
iframe.style.border = "none"
}
})
}
// in component that renders n iframes
<iframe
id={`${props.id}-iframe`}
src={(() => {
const html = [`data:text/html,${encodeURIComponent(props.thirdLineData)}`]
if (window.parent.postMessage) {
html.push(
`
<script>
window.onload = function(event) {
window.parent.postMessage(
{
height: document.body.scrollHeight,
id: "${props.id}-iframe",
origin: "company-name-iframe",
},
"${window.location.origin}"
);
};
</script>
`
)
}
return html.join("\n")
})()}
onLoad={(event) => {
// if the browser does not enforce a cross-origin policy,
// then just access the height directly instead
try {
const { target } = event
const contentDocument = (
target.contentDocument ||
// Earlier versions of IE or IE8+ where !DOCTYPE is not specified
target.contentWindow.document
)
if (contentDocument) {
target.style.height = `${contentDocument.body.scrollHeight}px`
}
} catch (error) {
const expectedError = (
`Blocked a frame with origin "${window.location.origin}" ` +
`from accessing a cross-origin frame.`
)
if (error.message !== expectedError) {
/* eslint-disable no-console */
console.err(
`An error (${error.message}) ocurred while trying to check to see ` +
"if the inner iframe is accessible or not depending " +
"on the browser cross-origin policy"
)
}
}
}}
/>
Here is an alternative implementation.
Basically if you able to edit page at other domain you can place another iframe page that belongs to your server which saving height to cookies.
With an interval read cookies when it is updated, update the height of the iframe. That is all.
Edit: 2019 December
The solution above basically uses another iframe inside of an iframe 3rd iframe is belongs to the top page domain, which you call this page with a query string that saves size value to a cookie, outer page checks this query with some interval. But it is not a good solution so you should follow this one:
In Top page :
window.addEventListener("message", (m)=>{iframeResizingFunction(m)});
Here you can check m.origin to see where is it comes from.
In frame page:
window.parent.postMessage({ width: 640, height:480 }, "*")
Although, please don't forget this is not so secure way. To make it secure update * value (targetOrigin) with your desired value.
Please follow documentation: https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage
I found another server side solution for web dev using PHP to get the size of an iframe.
First is using server script PHP to an external call via internal function: (like a file_get_contents with but curl and dom).
function curl_get_file_contents($url,$proxyActivation=false) {
global $proxy;
$c = curl_init();
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($c, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.8.1.7) Gecko/20070914 Firefox/2.0.0.7");
curl_setopt($c, CURLOPT_REFERER, $url);
curl_setopt($c, CURLOPT_URL, $url);
curl_setopt($c, CURLOPT_FOLLOWLOCATION, 1);
if($proxyActivation) {
curl_setopt($c, CURLOPT_PROXY, $proxy);
}
$contents = curl_exec($c);
curl_close($c);
$dom = new DOMDocument();
$dom->preserveWhiteSpace = false;
#$dom->loadHTML($contents);
$form = $dom->getElementsByTagName("body")->item(0);
if ($contents) //si on a du contenu
return $dom->saveHTML();
else
return FALSE;
}
$url = "http://www.google.com"; //Exernal url test to iframe
<html>
<head>
<script type="text/javascript">
</script>
<style type="text/css">
#iframe_reserve {
width: 560px;
height: 228px
}
</style>
</head>
<body>
<div id="iframe_reserve"><?php echo curl_get_file_contents($url); ?></div>
<iframe id="myiframe" src="http://www.google.com" scrolling="no" marginwidth="0" marginheight="0" frameborder="0" style="overflow:none; width:100%; display:none"></iframe>
<script type="text/javascript">
window.onload = function(){
document.getElementById("iframe_reserve").style.display = "block";
var divHeight = document.getElementById("iframe_reserve").clientHeight;
document.getElementById("iframe_reserve").style.display = "none";
document.getElementById("myiframe").style.display = "block";
document.getElementById("myiframe").style.height = divHeight;
alert(divHeight);
};
</script>
</body>
</html>
You need to display under the div (iframe_reserve) the html generated by the function call by using a simple echo curl_get_file_contents("location url iframe","activation proxy")
After doing this a body event function onload with javascript take height of the page iframe just with a simple control of the content div (iframe_reserve)
So I used divHeight = document.getElementById("iframe_reserve").clientHeight; to get height of the page external we are going to call after masked the div container (iframe_reserve). After this we load the iframe with its good height that's all.

Detecting if YouTube is blocked by company / ISP

We have YouTube videos on a site and want to detect if it is likely that they will not be able to view them due to (mostly likely) company policy or otherwise.
We have two sites:
1) Flex / Flash
2) HTML
I think with Flex I can attempt to download http://youtube.com/crossdomain.xml and if it is valid XML assume the site is available
But with HTML I don't know how to do it. I can't even think of a 'nice hack'.
I like lacker's solution, but yes, it creates a race condition.
This will work and won't create a race contition:
var image = new Image();
image.onload = function(){
// The user can access youtube
};
image.onerror = function(){
// The user can't access youtube
};
image.src = "http://youtube.com/favicon.ico";
You can load an image from youtube using javascript and check its properties. The favicon is tiny and has a consistent url -
var image = new Image();
image.src = "http://youtube.com/favicon.ico";
if (image.height > 0) {
// The user can access youtube
} else {
// The user can't access youtube
}
I think this is slightly better than loading javascript because this won't try to run any code, and while youtube might rename their javascript files, or functions from those files, they are unlikely to ever rename their favicon.
This should work. Basically, it loads a youtube.com javascript file, then checks if a function in that file exists.
<html>
<head>
<script src="http://www.youtube.com/js/account.js"></script>
<script>
function has_you_tube()
{
if(typeof addVideosToQuicklist == 'function')
{
return true;
}
else
{
return false;
}
}
</script>
</head>
<body>
<script>alert( "has_youtube: " + has_you_tube() ); </script>
</body>
</html>
I got stuck on this today and tried the favicon test but it wasnt working in IE. I was using the YouTube Player API Reference for iframe Embeds to embed youtube videos into my site so what I did is perform a check on the player var defined just before the onYouTubeIFrameReady with a delay on the javascript call.
<script> function YouTubeTester() {
if (player == undefined) {
alert("youtube blocked");
}
}
</script>
<script>window.setTimeout("YouTubeTester()", 500);</script>
Seems to work for me. I needed the delay to get it to work in IE.
This worked for me... Its also my first post, hope it helps some one too.
<?php
$v = file_get_contents("https://www.youtube.com/iframe_api");
//Tie counts to a variable
$test = substr_count($v, 'loading');
if ($test > 0)
{ ?>
<iframe>YOUTUBE VIDEO GOES HERE</iframe>
<?php
}
else
{
echo "<br/> no connection";
}
?>

Resources