I have added a css file on my page. But sometimes. the css file doesnt load and the page renders in Normal HTML style. If we refresh the page manually then it loads. This issue is intermittent for all the browsers. Is there any solution for this. Can we ensure that the css loads every time before the page renders?
Thanks,
Rohit
I have seen this issue a lot in web development and there seems to be no solution as far as I know. Even sites like YouTube and gmail will sometimes not load the CSS leading to the page being rendered in a jumbled fashion with a white background. If it seems to only happen on your site, try switching hosts; maybe that will help.
Good luck!
Edit: the only reason I don't think this is code related is because you said it happens intermittently. Have you tried testing on numerous machines, not just different browsers?
Make sure you put the style reference in <head> section of html and make sure the css markup are correct.
Style reference
<link href="SiteStyles.css" rel="stylesheet" type="text/css" />
You can load dynamically with JQuery
$(document).ready( function() {
$("head").append("<link>");
css = $("head").children(":last");
css.attr({
rel: "stylesheet",
type: "text/css",
href: "/css/stylesheet.css"
});
});
Or this one
$(document).ready( function() {
$("head").append("<link rel='stylesheet' type='text/css' href='css/style.css' />");
});
you can use this trick also not good but may be work
<script type="text/javascript" charset="utf-8">
$(document).ready(function(){
$("style").load("css/style.css")
})
</script>
This is the default behavior of the browser. Actually the browser caches the css file. But there is one way, you can do this, and that is to pass a query sting value as follows...
<link rel="stylesheet" type="text/css"
href="http://www.domain.com/css/abc.css?v=1.1" />
Related
i'm trying to optimize this website: electronicsportsitalia-it and when i try to analyze it on Google PageSpeed the platforms says that there is a google font blocking the page rendering:
https://fonts.googleapis.com/css?family=Lato:300,400,700
The font firstly was loaded through php but then i inserted it directly in html code trying to load it with this code: <link rel=stylesheet id=avia-google-webfont href='//fonts.googleapis.com/css?family=Lato:300,400,700' type='text/css' media=all lazyload> -put also before the </body> tag- but it didn't worked.
So i tryed to load it with Web Font Loader and actually the website is runnging this script:
`
</script>
<script>
WebFont.load({
google: {
families: ['Lato']
}
});
</script>`
but always the same problem on PageSpeed.
Can someone help me?
You can preload any styles (including google fonts)
<link
rel="preload"
href="https://fonts.googleapis.com/css?family=Open+Sans:300&display=swap"
as="style"
onload="this.onload=null;this.rel='stylesheet'"
/>
<noscript>
<link
href="https://fonts.googleapis.com/css?family=Open+Sans:300&display=swap"
rel="stylesheet"
type="text/css"
/>
</noscript>
You can read more on web.dev
UPDATE
Base on Lucas Vazquez comment I've also added &display=swap (which fixes this issue "Ensure text remains visible during webfont load")
You question boils down how to include less critical CSS asynchronously. I recommend to read this article.
Its similar to Claudiu's answer however, it is recommended in the article not to use preload, because of this:
First, browser support for preload is still not great, so a polyfill (such as the one loadCSS provides) is necessary if you want to rely on it to fetch and apply a stylesheet across browsers. More importantly though, preload fetches files very early, at the highest priority, potentially deprioritizing other important downloads, and that may be higher priority than you actually need for non-critical CSS
Here is the alternative:
<link
rel="stylesheet"
href="https://fonts.googleapis.com/css?family=Open+Sans:300&display=swap"
media="print"
onload="this.media='all'"
/>
<noscript>
<link
href="https://fonts.googleapis.com/css?family=Open+Sans:300&display=swap"
rel="stylesheet"
type="text/css"
/>
</noscript>
This is how it works. The attribute media=print will skip the css on page rendering. Once the page has loaded, it will load the print css. The onload JS event changes the media to all, now the font will be loaded and change the page rendering. Most importantly, the font will no longer render-block your page.
For the edge case, that a user has js disabled, the "noscript" tag will load the font directly.
You can take advantage of the onload attribute like this -
<link
href="https://fonts.googleapis.com/css?family=Open+Sans:400,600&display=swap"
rel="stylesheet"
type="text/css"
media="print"
onload="this.media='all'"
/>
Set the media attribute to print at first, but change it to all when the download callback fires.
I noticed that Laravel added this tag to its html head output recently:
<link rel="preconnect" href="https://fonts.gstatic.com">
I copied it and added it before my font request, i.e:
<link rel="preconnect" href="https://fonts.gstatic.com">
<link href="https://fonts.googleapis.com/css2?family=Montserrat&display=swap" rel="stylesheet" id="google-fonts-css">
This simple tag took me from a Mobile Pagespeed score of 80 up to 95, but I can't be entirely sure that it was in fact the tag I have to thank for this score increase - PageSpeed is unpredicatable. I'm not sure if it's just a Chrome thing or a new standard.
In my case, I will generate my font using a font-face generator tool which is easier to use and less hassle but when I use google fonts, this is what I do.
You can use style element at the end of body, just before the closing </body> tag:
<style>
#import "//fonts.googleapis.com/css?family=Lato:300,400,700"
</style>
or you can refer to How to keep CSS from render-blocking my website?
The following font files must be loaded before this JS file: https://electronicsportsitalia.it/wp-content/plugins/google-analytics-for-wordpress/assets/js/frontend.min.js
https://fonts.gstatic.com/s/lato/v14/EsvMC5un3kjyUhB9ZEPPwg.woff2
https://fonts.gstatic.com/s/opensans/v15/DXI1ORHCpsQm3Vp6mXoaTegdm0LZdjqr5-oayXSOefg.woff2
https://fonts.googleapis.com/css?family=Lato
https://fonts.gstatic.com/s/roboto/v18/RxZJdnzeo3R5zSexge8UUVtXRa8TVwTICgirnJhmVJw.woff2
https://fonts.gstatic.com/s/lato/v14/EsvMC5un3kjyUhB9ZEPPwg.woff2
I'm not seeing this issue in any other browser that I've tested - IE, Chrome, Opera - but whenever I load a page from the server, I'm seeing a flash of unstyled content before the CSS is applied.
This is even happening on subsequent page loads where everything should be cached - every time the page loads I see the unstyled content for a split-second, then everything settles in.
It's also worth noting (perhaps?) that the page is using #font-face to pull some Google fonts. They are stored in a separate stylesheet being pulled after the main responsive stylesheets and media queries.
I've tried a few different things, to no effect:
Rearranging order of CSS stylesheet links
Removing link to stylesheets with #font-face
Disabling Firebug? (Read on here somewhere...)
One other thing that may be worth mentioning is that I used quite a lot of Element Type CSS selectors in the page's CSS. Is it possible that this is slowing down the rendering process?
This seems unlikely as there is no problem immediately re-rendering the page upon changing the dimensions of the window - the responsive stuff renders fine immediately.
So this leads me to believe that there is some issue with how the CSS is being loaded.
Here is my HEAD code:
<!DOCTYPE html>
<head>
<!--<meta name="robots" content="noindex" />-->
<meta charset="utf-8">
<meta name="description" content="">
<meta name="viewport" content="width=device-width; initial-scale=1.0; maximum-scale=1.0; minimum-scale=1.0; user-scalable=no; target-densityDpi=device-dpi" />
<title></title>
<!-- responsive stylesheets -->
<link rel="stylesheet" href="resources/css/320.css" type="text/css" media="screen and (max-width:320px)" />
<link rel="stylesheet" href="resources/css/480.css" type="text/css" media="screen and (min-width:321px) and (max-width:480px)" />
<link rel="stylesheet" href="resources/css/768.css" type="text/css" media="screen and (min-width:481px) and (max-width:768px)" />
<link rel="stylesheet" href="resources/css/960.css" type="text/css" media="screen and (min-width:769px) and (max-width:960px)" />
<link rel="stylesheet" href="resources/css/960+.css" type="text/css" media="screen and (min-width:961px)" />
<!-- custom fonts stylesheet -->
<link rel="stylesheet" href="resources/css/fonts.css" type="text/css" />
<!-- favicon -->
<link rel="shortcut icon" href="resources/images/ui/favicon.ico">
<!--[if lt IE 9]>
<link rel="stylesheet" href="resources/css/960+.css" type="text/css"/>
<![endif]-->
</head>
WTF is going wrong with Firefox? It's driving me nuts!
If you add a dummy <script> tag right after <body>, Firefox will show the page after all the css from <head> is loaded:
<body>
<script>0</script>
<!-- rest of the code -->
</body>
There is an official bugreport about this FOUC (Flash Of Unstyled Content) on the Firefox site: https://bugzilla.mozilla.org/show_bug.cgi?id=1404468
I had the same problem with Layout was forced before the page was fully loaded. If stylesheets are not yet loaded this may cause a flash of unstyled content. showing in the console, and a visible flash of unstyled content upon page refresh, withouth (F5) or with clearing the cache (Ctrl + F5). Having the developer tools open does not made a difference either.
What helped me was declaring a variable in a script just before the </head> tag ended, so basically after all the <link> tags.
It's important to note, that an empty script (or with just a comment) or any random javaScript would not help, but declaring a variable worked.
<head>
<link rel="stylesheet" href="css/main.css" />
<link rel="stylesheet" href="css/other.css" />
<script>
/*to prevent Firefox FOUC, this must be here*/
let FF_FOUC_FIX;
</script>
</head>
There was no need to rearrange links or not use imports within css or js files.
Please note that the issue will no longer be visible (FOUC is visibly gone), but the console might still show the same warning.
I was experiencing this error. A colleague has said that it's caused by the attribute, autofocus being added to a form field.
By removing this attribute and using JavaScript to set the focus the brief flash of unstyled content stops happening.
For what it's worth, I had this same problem and found that it was being caused by having poorly formatted <html>...</html> tags.
To be precise, in my code I accidentally closed the HTML tag too early, like this:
<!DOCTYPE html>
<html lang="en"></html>
<head>
<title>My title</title>
The code provided by the original poster is missing the opening <html> so I suspect that's probably what is happening there.
Filament Group share they way they load their fonts in detail,
http://www.filamentgroup.com/lab/font-loading.html
which is a nice modern approach to #font-face loading
Smashing magazine also review there website performance and came up with a different solution that stores the caches a base64 copy of the font in local storage. This solution may require a different licence for you font.
A gist can be found at:
https://gist.github.com/hdragomir/8f00ce2581795fd7b1b7
The original article detailing their decision can be fount at:
http://www.smashingmagazine.com/2014/09/08/improving-smashing-magazine-performance-case-study/#webfonts
Additional recommendation
The head of your document contains far to many individual stylesheets, all these css files should be combined into a single file, minified and gziped. You may have a second link for your fonts placed before you main stylesheet.
<link rel="stylesheet" href="resources/css/fonts.css" type="text/css" />
<link rel="stylesheet" href="resources/css/main.css" type="text/css" />
I've had the same issue. In my case removing #import rule in the CSS file and linking all the CSS files in the HTML resolved it.
In my case the reason of FOUC in FF was the presence of iframe on page.
If I removing iframe from markup then FOUC disappears.
But I need iframe for my own hacking reasons so I changed this
<iframe name="hidden-iframe" style="display: none;position:absolute;"></iframe>
into this
<script>
document.addEventListener('DOMContentLoaded', ()=>{
let nBody = document.querySelector('body')
let nIframe = document.createElement('iframe');
nIframe.setAttribute('name', "hidden-iframe");
nIframe.style.display = 'none';
nIframe.style.position = 'absolute';
nBody.appendChild(nIframe);
});
</script>
I've added this inline JS right in template just for readability: in my case this code runs once per page.
I know that it's dirty hack, so you can add this code in separated JS-file.
The problem was in Firefox Quantum v65.
I had the same problem (but also in chrome). Even if many of the existing answers provide clues to the reason for FOUC I wanted to present my problem and its solution.
As I said, I had FOUC in a fairly large project and already had the suspicion of a racecondition in some form.
In the project SASS is used and via a "bootstrap" file for the css a fontawesome free package was added via import.
#import "#fortawesome/fontawesome-free/css/all.css";
This import has increased the total size of the css file by a lot, which caused the file to take a long time to load, and the browser went and already loaded the following javascript.
The JS that was then executed forced the rendering of its content and thus created the FOUC.
So the solution in my case was to remove the big fontawesome package and insert the icons I used from it (~10) via an Icomoon custom font. Not only did this solve the FOUC but it also had the nice side effect that the delivered CSS files are much smaller.
Suppose if I have a website http://somethingsomething.com
And I have 3 css file
common.css
homepage.css
inner-pages.css
homepage.css is required for homepage and common.css is for whole site but inner-pages.css is for other pages only and it's big file. Is it possible to load inner-pages.css after homepage data download. In the same way like we use async attribute for script tag. As far as I know async attribute is only for JS not CSS
my one friend suggested to use requirejs for this http://requirejs.org/docs/faq-advanced.html#css but I don't want to use javascript to load css and even I would think upon JS way i would not use require.js just for this. So if it is not possible with CSS only. what would be the simple JS way to do this?
Async CSS with media="bogus" and a <link> at the foot
Say we've got our HTML structured like this:
<head>
<!-- unimportant nonsense -->
<link rel="stylesheet" href="style.css" media="bogus">
</head>
<body>
<!-- other unimportant nonsense, such as content -->
<link rel="stylesheet" href="style.css">
</body>
More at http://codepen.io/Tigt/post/async-css-without-javascript
You can place an iframe in your page pointing to some dummy page that serves the CSS, that should serve the CSS file async.
<iframe src="loadcss.html"></iframe>
Do note it seems pretty trivial, this causes a minimum of 2 css file transfers per page and 3 css file transfers per child page (if it isn't cached). If you were to minify the css you would only have 1 transfer regardless.
try
$.ajax({
url:'/css.css',
type:'get',
success:function(css){
$('html').append('<style>'+css+'</style>');
}
});
or
function getCss(url){
$('<link>',{rel:'stylesheet',type:'text/css','href':url}).appendTo('head');
}
getCss('/css.css');
ok sorry I didn't see you don't want to use javascript
how about using css #import:
<style>
#import url('/style1.css');
#import url('/style2.css');
</style>
Include your CSS in the <body> instead of <head> ... "it seems this trick causes Chrome & Firefox to start the body earlier, and they simply don't block for body stylesheets." and add a condition for IE:
head
<head>
<!--[if IE]>
<link rel="stylesheet" href="style.css"> <!-- blocking, but what else can ya do? -->
<![endif]-->
</head>
body
<body>
<!--[if !IE]> -->
<link rel="stylesheet" href="style.css" lazyload>
<!-- <![endif]-->
</body>
by Taylor Hunt #codepen.io
As suggested Require is not necessary for loading CSS assets. If you want to get your larger payloads asynchronously without relying on JavaScript you should be looking at leveraging HTTP/2 Server Push to deliver your non-critical style assets. And here's a performance technique you may find useful for delivering critical CSS payloads for browsers which works well even today.
Finally, if you are optimizing your pages for performance and don't want to pull in heavy or complicated tools like Require I've an alternative minimal asset loader you may use if you like.
I have a web page, I want to detect whether it's running on mobile safari on an ipad. If so, it should load different css files (and if it is running on websheet then it should load another css).
I am using following way for handling css but it shows only one for both:
<link rel="stylesheet" href="main.css?v=2">
<link rel="stylesheet" media="handheld" href="css/handheld.css?v=2">
Are you using a programming language to dynamically generate pages? If so, you can use user-agent sent by browser and according to it, decide which css to include.
Example:
<script type="text/javascript">
$("#btn_load_css").click(function(){
var w = screen.width;
var h = screen.height;
$(document).append("<link rel='stylesheet' "
+" href='css/defaults.css.php?w="+w+"&h="+h+"' />");
});
</script>
This will cause the css to load at the end of the file.
If your main concern is the viewport size simply use media queries.
See MDN for an easier explanation and some examples.
How do I stop the flash of unstyled content (FOUC) on a web page?
The problem with using a css style to initially hide some page elements, and then using javascript to change the style back to visible after page load, is that people who don't have javascript enabled will never get to see those elements. So it's a solution which does not degrade gracefully.
A better way therefore, is to use javascript to both initially hide as well as redisplay those elements after page load. Using jQuery, we might be tempted to do something like this:
$(document).ready(function() {
$('body').hide();
$(window).on('load', function() {
$('body').show();
});
});
However, if your page is very big with a lot of elements, then this code won't be applied soon enough (the document body won't be ready soon enough) and you might still see a FOUC. However, there is one element that we CAN hide as soon as script is encountered in the head, even before the document is ready: the HTML tag. So we could do something like this:
<html>
<head>
<!-- Other stuff like title and meta tags go here -->
<style type="text/css">
.hidden {display:none;}
</style>
<script type="text/javascript" src="/scripts/jquery.js"></script>
<script type="text/javascript">
$('html').addClass('hidden');
$(document).ready(function() { // EDIT: From Adam Zerner's comment below: Rather use load: $(window).on('load', function () {...});
$('html').show(); // EDIT: Can also use $('html').removeClass('hidden');
});
</script>
</head>
<body>
<!-- Body Content -->
</body>
</html>
Note that the jQuery addClass() method is called *outside* of the .ready() (or better, .on('load')) method.
This is the one that has worked for me and does not require javascript and it works great for pages with many elements and lots of css:
First, add a dedicated <STYLE> setting for the <HTML> tag with visibility 'hidden' and opacity as '0' at the top of your HTML, e.g, in the beginning of the <HEAD> element, for example, at the top of your HTML add:
<!doctype html>
<html>
<head>
<style>html{visibility: hidden;opacity:0;}</style>
Then, at the end of your last .css stylesheet file, set the visibility and opacity styles to 'visible' and '1', respectively:
html {
visibility: visible;
opacity: 1;
}
If you already have an existing style block for the 'html' tag, then move the entire 'html' style to the end of the last .css file and add the 'visibility' and 'opacity' tags as described above.
https://gist.github.com/electrotype/7960ddcc44bc4aea07a35603d1c41cb0
A CSS-only solution:
<html>
<head>
<style>
html {
display: none;
}
</style>
...
</head>
<body>
...
<link rel="stylesheet" href="app.css"> <!-- should set html { display: block; } -->
</body>
</html>
As the browser parses through the HTML file:
The first thing it will do is hide <html>.
The last thing it will do is load the styles, and then display all the content with styling applied.
The advantage to this over a solution that uses JavaScript is that it will work for users even if they have JavaScript disabled.
Note: you are allowed to put <link> inside of <body>. I do see it as a downside though, because it violates common practice. It would be nice if there was a defer attribute for <link> like there is for <script>, because that would allow us to put it in the <head> and still accomplish our goal.
A solution which doesn't depend on jQuery, which will work on all current browsers and do nothing on old browsers, include the following in your head tag:
<head>
...
<style type="text/css">
.fouc-fix { display:none; }
</style>
<script type="text/javascript">
try {
var elm=document.getElementsByTagName("html")[0];
var old=elm.class || "";
elm.class=old+" fouc-fix";
document.addEventListener("DOMContentLoaded",function(event) {
elm.class=old;
});
}
catch(thr) {
}
</script>
</head>
Thanks to #justastudent, I tried just setting elm.style.display="none"; and it appears to work as desired, at least in current Firefox Quantum. So here is a more compact solution, being, so far, the simplest thing I've found that works.
<script type="text/javascript">
var elm=document.getElementsByTagName("html")[0];
elm.style.display="none";
document.addEventListener("DOMContentLoaded",function(event) { elm.style.display="block"; });
</script>
An other quick fix which also works in Firefox Quantum is an empty <script> tag in the <head>. This however, penalizes your pagespeed insights and overall load time.
I had 100% success with it. I think it's also the main reason, why above solutions with other JS in the works.
<script type="text/javascript">
</script>
None of the CSS-only solutions presented here work with modern browsers (asynchronous loading of css and fonts). You have to use Javascript. What I've done to avoid FOUC is:
<html>
<body onload="document.body.style.visibility=`visible`;">
<script>document.body.style.visibility=`hidden`;</script>
With this approach the body of my web page is kept hidden until the full page and CSS files are loaded. Once everything is loaded, the onload event turns the body visible. So, the web browser remains empty until a point when everything pops up on the screen.
It is a simple solution but so far it is working.
This will not affect users who have disabled Javascript because the <script> tag is ignored.
No one has talked about CSS #import
That was the problem for me i was loading two extra style sheets directly in my css file with #import
Simple solution: Replace all #import links with <link />
Every answer on this page slows down the load and it only hides the underlying issue. If you're experiencing FOUC, find out WHY it's happening and fix that.
At the core, this is happening:
because your stylesheets are not being loaded correctly: they should be loaded via link tag in the HTML, not via JavaScript
because you placed script tags before link tags, which may force a "layout operation" and trick the browser into rendering before it even attempts to load the style.
For reference, here's an example of FOUC:
I came up with a way that requires no real code change whatsoever, woohoo! My issue was related to importing several css files AFTER some javascript files.
To resolve the issue I just moved my CSS links so that they would be above my javascript imports. This allowed all my CSS to be imported and ready to go ASAP, so that when the HTML appears on the screen, even if the JS isn't ready, the page will be properly formatted
Here is my code .. hope it solve your problem
set <body style="opacity:0;">
<script>
$(document).ready(function() {
$("body").css('opacity', 1);
});
</script>
A simple solution to avoid a flash of unstyled content without javascript:
<!DOCTYPE html>
<html>
<head>
<title>Bla bla</title>
<link href="..." rel="stylesheet" />
<link href="..." rel="stylesheet" />
</head>
<body style="opacity: 0">
<!-- All HTML content here -->
<script src="..."></script>
<script src="..."></script>
<style>
body {
opacity: 1 !important;
}
</style>
</body>
</html>
When the parser arrives at the body, it is faded out using "opacity: 0". When the parser finally arrives at the very bottom after everything else is parsed, the body is faded in again using an in-page style. The !important keyword there is important ;-), because it overrules the previous inline style of the body tag.
In this case, using "opacity: 0" to fade out is better than "display: none", because if you have layout operations done by javascript, they may not work when the affected element is not rendered.
That worked for me.
The best solution I found till now is like this:
Add all styles of your header to a <style/> tag in <head/>
at the top of style tag add .not-visible-first{visibility: hidden} + other header style
Add css via JS at the end of body
document.getElementsByTagName("head")[0].insertAdjacentHTML("beforeend","<link rel=\"stylesheet\" href=\"/css/main.min.css?v=1.2.4338\" />");
And remember to add .not-visible-first{visibility: visible} to the end of main.min.css
This option will create better user experience
You could try this with vanilla
function js_method(){
//todos
var elementDiv = document.getElementById("main");
elementDiv.style.display ="block";
}
<body onload="js_method()" id="main" style="display:none">
//todos
<h2>Hello</h2>
</body>