I have a simple HTML page with an iframe. I set its src to another HTML
file and I can change the style of any chosen element at will using code
like this (a basic example):
function elementStyle()
{
var iFrame = document.getElementById( "iFrame" );
var element = iFrame.contentWindow.document.getElementsByTagName(
"table" )[0];
element.style.color = "#ff0000";
}
However the src of the iframe must be an external URL and cross-domain
restriction prevents me from accessing its elements. I have no control
over its content so I can't use postMessage() because I can't receive
any message posted.
Any ideas of a way to get round this?
Note: it must work for anyone with any browser so musn't use any special
methods (like jQuery, CORS etc).
Thanks
When my iframe loads I need parent page to load different content(header,footer) while iframe its still there. I added to iframe :
window.top.location = "http://mysite.com";
It loads the new parent page but its reloading over and over again.
How can I enable only one load/iframe load, or some solution.
I have tried with
window.onload = function() {
if(!window.location.hash) {
window.location = window.location + '#loaded';
window.location.reload();
}
}
but it does nothing.
Thank you.
you just can't reload the iframe parent only without reloading the iframe too! If you want to change some content in parent page you must do it with javascript from the parent page and not the iframe.
And if you want to catch the "iframe loaded event" you must do it from inside the iframe. Looks like an impossible situation but you can still do it!
You need to let iframe and parent page comunicate, and you can do it with html5 postmessage (works even if parent and iframe are in different domains!). If you need to have IE7 compatibility too you can use easyXDM javascript library instead of postMessage, just search for example in their site.
Simply do a postMessage from iFrame when jQuery(document).ready() (or any similar event) is triggered, the parent page must have a listner waiting for this message for trigger the header/footer/anything change event.
On my page I have some images on thisdomain.com/images. on document.ready(), I change the src attribute of images to thatdomain.com/images. Firebug's Net tab shows me that images are downloaded from both thisdomain.com and thatdomain.com. How can I prevent the browser from downloading images from thisdomain.com?
$(document).ready(function(){
$("img").each(function() {
var $img = $(this);
var src = $img.attr("src");
$img.attr("src", src.replace(/thisdomain.com.com\/images/i, "thatdomain.com\/images"));
});
});
EDIT: ASP.NET server-side override of Render() using code "in front" i.e., <script runat="server"> I just added this to the aspx page without recompiling code-behind. It's a bit hack-ish but it works.
<script runat="server">
static Regex rgx = new Regex(#"thisdomain.com/images", RegexOptions.Compiled | RegexOptions.IgnoreCase);
protected override void Render(System.Web.UI.HtmlTextWriter writer)
{
using (HtmlTextWriter htmlwriter = new HtmlTextWriter(new System.IO.StringWriter()))
{
base.Render(htmlwriter);
string html = htmlwriter.InnerWriter.ToString();
string newHtml = rgx.Replace(html, "thatdomain.com/images");
writer.Write(newHtml.Trim());
}
}
</script>
This sounds like something that is impossible to achieve reliably, because images will start to load asynchronously as soon as a src has been specified.
I can't think of a workaround. The <base> tag would allow for some kind of "mass redirection" but the URIs would have to be relative ones for that to work.
I'm sure you have your reasons for outputting thisdomain.com in the first place, but I'm pretty sure you'll have to change your code so thatdomain.com gets output instead (or no src gets specified at all so you can add them using jQuery) if you want a 100% watertight solution.
This ain't going to work in the client side. Your best bet is a server side solution. Have the server side script (PHP? JSP? ASP? etc) to read the to-be-included HTML source and replace the src's accordingly with help of a decent DOM parser before it get emitted to the client side.
I don't that is possible at all. To use jQuery functions, the jQuery library needs to be downloaded, which probably means the browser already started downloading other assets, such as images.
You can't be completely sure to prevent downloading by changing the URL after the element has been parsed. The closest possible that you can get is by changing it immediately after the element:
<img id="something" src="http://www.thisdomain.com/images/hello.gif" />
<script type="text/javascript">
var $img = $('#something');
$img.attr("src", $img.attr("src").replace(/thisdomain.com\/images/i, "thatdomain.com\/images"));
</script>
I don't think there is a way to halt GET requests from img elements once the page has loaded. It's difficult to suggest an alternative since I'm not sure what you're trying to achieve.
Can you be more specific?
Is it possible to change styles of a div that resides inside an iframe on the page using CSS only?
You need JavaScript. It is the same as doing it in the parent page, except you must prefix your JavaScript command with the name of the iframe.
Remember, the same origin policy applies, so you can only do this to an iframe element which is coming from your own server.
I use the Prototype framework to make it easier:
frame1.$('mydiv').style.border = '1px solid #000000'
or
frame1.$('mydiv').addClassName('withborder')
In short no.
You can not apply CSS to HTML that is loaded in an iframe, unless you have control over the page loaded in the iframe due to cross-domain resource restrictions.
Yes. Take a look at this other thread for details:
How to apply CSS to iframe?
const cssLink = document.createElement("link");
cssLink.href = "style.css";
cssLink.rel = "stylesheet";
cssLink.type = "text/css";
frames['frame1'].contentWindow.document.body.appendChild(cssLink);
// ^frame1 is the #id of the iframe: <iframe id="frame1">
You can retrieve the contents of an iframe first and then use jQuery selectors against them as usual.
$("#iframe-id").contents().find("img").attr("style","width:100%;height:100%")
$("#iframe-id").contents().find("img").addClass("fancy-zoom")
$("#iframe-id").contents().find("img").onclick(function(){ zoomit($(this)); });
Good Luck!
The quick answer is: No, sorry.
It's not possible using just CSS. You basically need to have control over the iframe content in order to style it. There are methods using javascript or your web language of choice (which I've read a little about, but am not to familiar with myself) to insert some needed styles dynamically, but you would need direct control over the iframe content, which it sounds like you do not have.
Use Jquery and wait till the source is loaded,
This is how I have achieved(Used angular interval, you can use javascript setInterval method):
var addCssToIframe = function() {
if ($('#myIframe').contents().find("head") != undefined) {
$('#myIframe')
.contents()
.find("head")
.append(
'<link rel="stylesheet" href="app/css/iframe.css" type="text/css" />');
$interval.cancel(addCssInterval);
}
};
var addCssInterval = $interval(addCssToIframe, 500, 0, false);
Combining the different solutions, this is what worked for me.
$(document).ready(function () {
$('iframe').on('load', function() {
$("iframe").contents().find("#back-link").css("display", "none");
});
});
Apparently it can be done via jQuery:
$('iframe').load( function() {
$('iframe').contents().find("head")
.append($("<style type='text/css'> .my-class{display:none;} </style>"));
});
https://stackoverflow.com/a/13959836/1625795
probably not the way you are thinking. the iframe would have to <link> in the css file too. AND you can't do it even with javascript if it's on a different domain.
Not possible from client side . A javascript error will be raised "Error: Permission denied to access property "document"" since the Iframe is not part of your domaine.
The only solution is to fetch the page from the server side code and change the needed CSS.
A sort of hack-ish way of doing things is like Eugene said. I ended up following his code and linking to my custom Css for the page. The problem for me was that, With a twitter timeline you have to do some sidestepping of twitter to override their code a smidgen. Now we have a rolling timeline with our css to it, I.E. Larger font, proper line height and making the scrollbar hidden for heights larger than their limits.
var c = document.createElement('link');
setTimeout(frames[0].document.body.appendChild(c),500); // Mileage varies by connection. Bump 500 a bit higher if necessary
Just add this and all works well:
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
If the iframe comes from another server, you will have CORS ERRORS like:
Uncaught DOMException: Blocked a frame with origin "https://your-site.com" from accessing a cross-origin frame.
Only in the case you have control of both pages, you can use https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage to safely send messages like this:
On you main site(one that loads the iframe):
const iframe = document.querySelector('#frame-id');
iframe.contentWindow.postMessage(/*any variable or object here*/, 'https://iframe-site.example.com');
on the iframe site:
// Called sometime after postMessage is called
window.addEventListener("message", (event) => {
// Do we trust the sender of this message?
if (event.origin !== "http://your-main-site.com")
return;
...
...
});
Yes, it's possible although cumbersome. You would need to print/echo the HTML of the page into the body of your page then apply a CSS rule change function. Using the same examples given above, you would essentially be using a parsing method of finding the divs in the page, and then applying the CSS to it and then reprinting/echoing it out to the end user. I don't need this so I don't want to code that function into every item in the CSS of another webpage just to aphtply.
References:
Printing content of IFRAME
Accessing and printing HTML source code using PHP or JavaScript
http://www.w3schools.com/js/js_htmldom_html.asp
http://www.w3schools.com/js/js_htmldom_css.asp
How do I use the JavaScript DOM to apply onclick events to links inside of an iframe?
Here's what I'm trying that isn't working:
document.getElementById('myIframe').contentDocument.getElementsByTagName('a').onclick = function();
No errors seem to be thrown, and I have complete control of the stuff in the iframe.
Here is some code to test and see if I can at least count how many div's are in my iframe.
// access body
var docBody = document.getElementsByTagName("body")[0];
// create and load iframe element
var embed_results = document.createElement('iframe');
embed_results.id = "myIframe";
embed_results.setAttribute("src", "http://www.mysite.com/syndication/php/embed.php");
// append to body
docBody.appendChild(embed_results);
// count the divs in iframe and alert
alert(document.getElementById("myIframe").contentDocument.getElementsByTagName('div').length);
It is possible for an iFrame to source content from another website on a different domain.
Being able to access content on other domains would represent a security vulnerability to the user and so it is not possible to do this via Javascript.
For this reason, you can not attach events in your page to content within an iFrame.
getElementsByTagName returns a NodeCollection, so you have to iterate throgh this collection and add onclick handler to every node in that collection. The code below should work.
var links = document.getElementById('myIframe').contentDocument.getElementsByTagName('a');
for(var i=0;i<links.length;++i)links[i].onclick=function(){}
also make sure, you run this code after the frames' content is loaded
embed_results.onload=function(){
// your code
}