Related
im trying to download a file that constructs itself based on the value it recives. This is my code
<html>
<head>
<script>
var myList=[];
window.onmessage = function(event){
if (event.data) {
myList = event.data;
if (myList.length>0) {
buildHtmlTable();
}
}
else {
myList = [];
}
};
function buildHtmlTable() {
var columns = addAllColumnHeaders(myList);
for (var i = 0 ; i < myList.length ; i++) {
var row$ = $('<tr/>');
for (var colIndex = 0 ; colIndex < columns.length ; colIndex++) {
var cellValue = myList[i][columns[colIndex]];
if (cellValue == null) { cellValue = ""; }
row$.append($('<td/>').html(cellValue));
}
$("#excelDataTable").append(row$);
}
return exportF(); // Make Excel file download now
}
function addAllColumnHeaders(myList)
{
var columnSet = [];
var headerTr$ = $('<tr/>');
for (var i = 0 ; i < myList.length ; i++) {
var rowHash =`enter code here` myList[i];
for (var key in rowHash) {
if ($.inArray(key, columnSet) == -1){
columnSet.push(key);
headerTr$.append($('<th/>').html(key));
}
}
}
$("#excelDataTable").append(headerTr$);
return columnSet;
}
function exportF() {
var table = document.getElementById("excelDataTable");
var html = table.outerHTML;
var url = 'data:application/vnd.ms-excel,' + escape(html);
var link = document.getElementById("downloadLink");
link.setAttribute("href", url);
link.setAttribute("download", "export.xls"); // Choose the file name here
link.click(); // Download your excel file
return false;
}
</script>
</head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<body onLoad="">
<table id="excelDataTable" border="1">
</table>
<a style="display: none" id="downloadLink"></a>
</body>
</html>
The code itself works, but the error i get is "Download is disallowed. The frame initiating or instantiating the download is sandboxed, but the flag ‘allow-downloads’ is not set. See https://www.chromestatus.com/feature/5706745674465280 for more details."
What can i do to work around this? It feels like ive tried everything i can get my hands on but nothing seems to work for it to download
As the warning message says, you can't initialize downloads from a sandboxed iframe if it doesn't have the allow-downloads permission.
All solutions will imply having access to the page where the iframe is displayed (hereafter "the embedder").
The easiest and recommended way,
is to ask the embedder to add this permission when they define their iframe:
<iframe src="yourpage.html" sandbox="allow-scripts allow-downloads"></iframe>
An other way would be to ask them to not sandbox that iframe at all,
<iframe src="yourpage.html"></iframe>
but I guess that if they did, it's because they don't trust your page enough.
Finally a more complex way would be to pass the generated file back to the parent window.
For this you'd need to define a new API with your clients.
You could obviously just emit a global message event back to them, but I guess the cleanest is to make them pass a MessageChannel's MessagePort along with the myList data, so they can wait for the response there easily and be sure they'll only catch the response and no other unrelated message.
So in the embedder page they'd do
frame.onload = (evt) => {
const channel = new MessageChannel();
// handle the response from the iframe
channel.port2.onmessage = (evt) => {
const file = evt.data;
saveAs( file, "file.html" ); // the embedder is reponsible to initialize the download
};
frame.contentWindow.postMessage( embedders_data, [ channel.port1 ] );
};
And in your page you'd do
window.onmessage = (evt) => {
const myList = evt.data;
// get the MessageChannel's port out of the transfer-list
const port = evt.ports[ 0 ];
// buildHtmlTable has to return the final file, not to make it download
const file = buildHtmlTable( myList );
if( port ) {
port.postMessage( file ); // send back to embedder
}
};
See it as a live plnkr.
Ps: note that your files are not xlsx files but HTML markup.
The correct answer
Under normal circumstances Kaiido's answer is indeed the correct solution to your problem. They will NOT work in your case though.
The answer that will work on WixSince you are using Wix there is no way for you to directly edit the Sandbox attribute of the iframe element. This is just how Wix does things. You can, however, use custom code (only applies to premium websites) to get the class name of the iframe and programatically use javascript to set the new attribute to the existing iframe.
You must use the web inspector to find out the class name (iframes in Wix do not have ids) then add "allow-downloads" to the sandbox attribute. You might then need to reload the iframe using js as well. Go to your website's settings -> Custom Code -> Create custom code at the end of the body tag
If you do not have a premium website then you unfortunately cannot do this. This is due to Wix's own limitations as a platform. If this is an absolute "must" for you project, I recommend you to not use Wix since they limit your freedom as a developer when it comes to working with
technologies that were not made by them. Not to mention that they lock features such as custom elements behind a pay wall. So we can't even test our ideas before committing to a hosting plan. For anyone reading this in the future, take this into consideration and look into other platforms.
Thanks for answers, i didnt find a sollution with the recomended answers. What i did is that i made a completely new page, instead of initializing a html iframe i redirected the current window to the new page i created. The new page took a variable from "www.page.com/?page={value} and downloaded what i needed from there instead. Its messy but it works so if anyone else has this problem i recomend this if you are using wix.
Plain JS - please no jQuery suggestions - it is for a bookmarklet that needs to use as plain JS as possible.
I hope someone KNOWS the answer since I cannot reliable create a fiddle.
This code will run in the scope of the page it is inserted in - it works perfectly in Fx6-9, safari and latest Chromes on Windows XP and OSX - Only IE gives me undefined when I try to access the iFrame
var zContainer = document.getElementById('zContainer');
if (zContainer==null) {
zContainer = document.createElement("div");
zContainer.id="zContainer";
document.body.appendChild(zContainer);
}
var zStuff = {}; // minimise window var footprint
zStuff.html = '<body>Hello</body>';
if (!zFrame) { // did we already have one?
zFrame = document.createElement("iframe");
zFrame.id="zIframeId"; zFrame.name="zIframeName"; zFrame.frameBorder="0";
zIFS = zFrame.style; zIFS.border="0"; zIFS.width="500px"; zIFS.height="500px"; zIFS.backgroundColor="white"; zIFS.display="block";
zContainer.appendChild(zFrame); // append to div
zFrame = window.frames["zIframeName"]; // undefined in IE8 !!!!!
// zFrame = document.getElementById("zIframeId"); // undefined in IE8 !!!!!
zFrame.src="javascript:'<body></body>'"; // initialise body
zFrame.document.write(zStuff.html); // or zFrame.contentDocument.write
zFrame.document.close();
// zFrame.document.body.innerHTML=zStuff.html; // also does not work
// zFrame.src="javascript:'"+zStuff.html+"'"; // alternative method - either one works in Fx/Chrome
}
Thanks for any hints and for not voting this down. I hope the SO community will be as
helpful to me as I have been to it over the last year and a half...
Update - since the code I posted had some remnants of desperation, I changed it to
if (!zFrame) { // did we already have one?
zFrame = document.createElement("iframe");
zFrame.id="zIframeId"; zFrame.name="zIframeName"; zFrame.frameBorder="0";
zIFS = zFrame.style; zIFS.border="0"; zIFS.width="500px"; zIFS.height="500px"; zIFS.backgroundColor="white"; zIFS.display="block";
zContainer.appendChild(zFrame); // append to div
zFrame.src="javascript:'<body></body>'"; // initialise body
zFrame.document.write(zStuff.html); // or zFrame.contentDocument.write
zFrame.document.close();
}
the above now replaces the page I am on with the code in the zStuff.html
instead of replacing only the iFrame content - it also broke in Fx
Now I have to do this in Fx which IE also does not mind but still replaces the window and not the iFrame
if (!zFrame) {
zFrame = document.createElement("iframe");
zFrame.scrolling="no"; zFrame.id="zIframeId"; zFrame.name="zIframeName"; zFrame.frameBorder="0";
zIFS = zFrame.style; zIFS.border="0px none"; zIFS.width="549px"; zIFS.height="510px"; zIFS.backgroundColor="white"; zIFS.display="block";
zDRContainer.appendChild(zFrame);
zFrame.src="javascript:'<body></body>'";
setTimeout(function() {
var zFrame = window.frames["zIframeName"]; // this is needed for the document.write
zFrame.document.write(zStuff.html);
zFrame.document.close();
},100);
}
The hack I suggested in chat:
var a = setInterval( function(){
try{
zFrame.contentWindow.document.write(zStuff.html);
zFrame.contentWindow.document.close();
clearInterval(a);
}
catch(e){}
}, 10 );
Since it is not known when IE allows accessing contentWindow properties, this will keep trying until it is allowed.
Is there any good way to detect when a page isn't going to display in a frame because of the X-Frame-Options header? I know I can request the page serverside and look for the header, but I was curious if the browser has any mechanism for catching this error.
OK, this one is old but still relevant.
Fact:
When an iframe loads a url which is blocked by a X-Frame-Options the loading time is very short.
Hack:
So if the onload occurs immediately I know it's probably a X-Frame-Options issue.
Disclaimer:
This is probably one of the 'hackiest' code I've written, so don't expect much:
var timepast=false;
var iframe = document.createElement("iframe");
iframe.style.cssText = "position:fixed; top:0px; left:0px; bottom:0px; right:0px; width:100%; height:100%; border:none; margin:0; padding:0; overflow:hidden; z-index:999999;";
iframe.src = "http://pix.do"; // This will work
//iframe.src = "http://google.com"; // This won't work
iframe.id = "theFrame";
// If more then 500ms past that means a page is loading inside the iFrame
setTimeout(function() {
timepast = true;
},500);
if (iframe.attachEvent){
iframe.attachEvent("onload", function(){
if(timepast) {
console.log("It's PROBABLY OK");
}
else {
console.log("It's PROBABLY NOT OK");
}
});
}
else {
iframe.onload = function(){
if(timepast) {
console.log("It's PROBABLY OK");
}
else {
console.log("It's PROBABLY NOT OK");
}
};
}
document.body.appendChild(iframe);
Disclaimer: this answer I wrote in 2012(Chrome was version ~20 at that time) is outdated and I'll keep it here for historical purposes only. Read and use at your own risk.
Ok, this is a bit old question, but here's what I found out (it's not a complete answer) for Chrome/Chromium.
the way do detect if a frame pointing to a foreign address has loaded is simply to try to access its contentWindow or document.
here's the code I used:
element.innerHTML = '<iframe class="innerPopupIframe" width="100%" height="100%" src="'+href+'"></iframe>';
myframe = $(element).find('iframe');
then, later:
try {
var letstrythis = myframe.contentWindow;
} catch(ex) {
alert('the frame has surely started loading');
}
the fact is, if the X-Frame-Options forbid access, then myFrame.contentWindow will be accessible.
the problem here is what I called "then, later". I haven't figured out yet on what to rely, which event to subsribe to find when is the good time to perform the test.
This is based on #Iftach's answer, but is a slightly less hacky.
It checks to see if iframe.contentWindow.length > 0 which would suggest that the iframe has successfully loaded.
Additionally, it checks to see if the iframe onload event has fired within 5s and alerts that too. This catches failed loading of mixed content (in an albeit hacky manner).
var iframeLoaded = false;
var iframe = document.createElement('iframe');
// ***** SWAP THE `iframe.src` VALUE BELOW FOR DIFFERENT RESULTS ***** //
// iframe.src = "https://davidsimpson.me"; // This will work
iframe.src = "https://google.com"; // This won't work
iframe.id = 'theFrame';
iframe.style.cssText = 'position:fixed; top:40px; left:10px; bottom:10px;'
+ 'right:10px; width:100%; height:100%; border:none; margin:0; padding:0; overflow:hidden; z-index:999999;';
var iframeOnloadEvent = function () {
iframeLoaded = true;
var consoleDiv = document.getElementById('console');
if (iframe.contentWindow.length > 0) {
consoleDiv.innerHTML = '✔ Content window loaded: ' + iframe.src;
consoleDiv.style.cssText = 'color: green;'
} else {
consoleDiv.innerHTML = '✘ Content window failed to load: ' + iframe.src;
consoleDiv.style.cssText = 'color: red;'
}
}
if (iframe.attachEvent){
iframe.attachEvent('onload', iframeOnloadEvent);
} else {
iframe.onload = iframeOnloadEvent;
}
document.body.appendChild(iframe);
// iframe.onload event doesn't trigger in firefox if loading mixed content (http iframe in https parent) and it is blocked.
setTimeout(function () {
if (iframeLoaded === false) {
console.error('%c✘ iframe failed to load within 5s', 'font-size: 2em;');
consoleDiv.innerHTML = '✘ iframe failed to load within 5s: ' + iframe.src;
consoleDiv.style.cssText = 'color: red;'
}
}, 5000);
Live demo here - https://jsfiddle.net/dvdsmpsn/7qusz4q3/ - so you can test it in the relevant browsers.
At time of writing, it works on the current version on Chrome, Safari, Opera, Firefox, Vivaldi & Internet Explorer 11. I've not tested it in other browsers.
The only thing I can think of is to proxy an AJAX request for the url, then look at the headers, and if it doesn't have X-Frame-Options, then show it in the iframe. Far from ideal, but better than nothing.
At least in Chrome, you can notice the failure to load because the iframe.onload event doesn't trigger. You could use that as an indicator that the page might not allow iframing.
Online test tools might be useful.
I used https://www.hurl.it/.
you can clearly see the response header.
Look for X-frame-option. if value is deny - It will not display in iframe.
same origin- only from the same domain,
allow- will allow from specific websites.
If you want to try another tool, you can simply google for 'http request test online'.
This is how I had checked for X-Frames-Options for one of my requirements. On load of a JSP page, you can use AJAX to send an asynchronous request to the specific URL as follows:
var request = new XMLHttpRequest();
request.open('GET', <insert_URL_here>, false);
request.send(null);
After this is done, you can read the response headers received as follows:
var headers = request.getAllResponseHeaders();
You can then iterate over this to find out the value of the X-Frames-Options. Once you have the value, you can use it in an appropriate logic.
This can be achieved through
a) Create a new IFrame through CreateElement
b) Set its display as 'none'
c) Load the URL through the src attribute
d) In order to wait for the iframe to load, use the SetTimeOut method to delay a function call (i had delayed the call by 10 sec)
e) In that function, check for the ContentWindow length.
f) if the length > 0, then the url is loaded else URL is not loaded due to X-Frame-Options
Below is the sample code:
function isLoaded(val) {
var elemId = document.getElementById('ctlx');
if (elemId != null)
document.body.removeChild(elemId);
var obj= document.createElement('iframe');
obj.setAttribute("id", "ctlx");
obj.src = val;
obj.style.display = 'none';
document.body.appendChild(obj);
setTimeout(canLoad, 10000);
}
function canLoad() {
//var elemId = document.getElementById('ctl100');
var elemId = document.getElementById('ctlx');
if (elemId.contentWindow.length > 0) {
elemId.style.display = 'inline';
}
else {
elemId.src = '';
elemId.style.display = 'none';
alert('not supported');
}
}
Solution: The problem below was caused by a Divx javascript that overwrote a core javascript function. Thanks to aeno for discovering this and shame on the Divx coder who did that!
Problem: Clicking the insert image button in the tinymce toolbar does nothing in IE8.
Description: Bear with me here. I don't think the issue is with tinymce and it's probably the fault of IE8, but I need help from someone wiser than me in solving the final piece of the puzzle to figure out who is responsible for this...
So basically I'm using tinyMCE with Visual Studio 2010 and I get the problem as described above. So I switch to the tinyMCE source code to debug this. The problem seems to happen in this piece of the code in the inlinepopups/editor_plugin_src.js, line 358:
_addAll : function(te, ne) {
var i, n, t = this, dom = tinymce.DOM;
if (is(ne, 'string'))
te.appendChild(dom.doc.createTextNode(ne));
else if (ne.length) {
te = te.appendChild(dom.create(ne[0], ne[1]));
for (i=2; i<ne.length; i++)
t._addAll(te, ne[i]);
}
},
the exact line of code being,
te = te.appendChild(dom.create(ne[0], ne[1]));
In IE8 te becomes null because te.appendChild returns nothing.
To give some background on the the code, te is a DOM.doc.body object and ne seems to be a json object containing the structure of the inline popup object that needs to be created.
So back to the code.. this works with all other browsers no problem. So I step into the function appendChild and I'm brought to some "JScript - script block [dynamic]" file that does the unthinkable. It overrides the doc.body.appendChild function... You can see it below,
code cut out
...
var appendChildOriginal = doc.body.appendChild;
doc.body.appendChild = function(element)
{
appendChildOriginal(element);
var tag = element.tagName.toLowerCase();
if ("video" == tag)
{
ProcessVideoElement(element);
}
}
...
code cut out
Here we can obviously see what went wrong. Of course te.appendChild returns nothing... it has NO RETURN STATEMENT!
So the final piece to this puzzle is wtf is this dynamic script block? I can't for the love of god figure out where this script block is coming from (VS2010 is not helping). My deepest suspicions are that this is IE8 in built? Can anyone shed some light on this? Below I'm providing a little bit more of this mysterious script block in case anyone can figure out where it's from. I can promise you something right now, it doesn't belong to any of the scripts in our project since we've done a search and we turn up with nothing.
var doc;
var objectTag = "embed";
// detect browser type here
var isInternetExplorer = (-1 != navigator.userAgent.indexOf("MSIE"));
var isMozillaFirefox = (-1 != navigator.userAgent.indexOf("Firefox"));
var isGoogleChrome = (-1 != navigator.userAgent.indexOf("Chrome"));
var isAppleSafari = (-1 != navigator.userAgent.indexOf("Safari"));
// universal cross-browser loader
if (isInternetExplorer)
{
// use <object> tag for Internet Explorer
objectTag = "object";
// just execute script
ReplaceVideoElements();
}
else if (isMozillaFirefox)
{
// listen for the 'DOMContentLoaded' event and then execute script
function OnDOMContentLoadedHandled(e)
{
ReplaceVideoElements();
}
window.addEventListener("DOMContentLoaded", OnDOMContentLoadedHandled, false);
}
else if (isGoogleChrome)
{
// just execute script
ReplaceVideoElements();
}
else if (isAppleSafari)
{
// listen for the 'DOMContentLoaded' event and then execute script
function OnDOMContentLoadedHandled(e)
{
ReplaceVideoElements();
}
window.addEventListener("DOMContentLoaded", OnDOMContentLoadedHandled, false);
}
function MessageHandler(event)
{
//window.addEventListener("load", OnLoad, false);
}
// replacing script
function ReplaceVideoElements()
{
if (isMozillaFirefox)
{
doc = window.content.document;
}
else
{
doc = document;
}
// set up DOM events for Google Chrome & Mozilla Firefox
if (isMozillaFirefox || isGoogleChrome || isAppleSafari)
{
doc.addEventListener("DOMNodeInserted", onDOMNodeInserted, false);
doc.addEventListener("DOMNodeInsertedIntoDocument", onDOMNodeInsertedIntoDocument, false);
}
// HACK : override appendChild, replaceChild, insertBefore for IE, since it doesn't support DOM events
if (isInternetExplorer)
{
var appendChildOriginal = doc.body.appendChild;
doc.body.appendChild = function(element)
{
appendChildOriginal(element);
var tag = element.tagName.toLowerCase();
if ("video" == tag)
{
ProcessVideoElement(element);
}
}
var replaceChildOriginal = doc.body.replaceChild;
doc.body.replaceChild = function(element, reference)
{
replaceChildOriginal(element, reference);
var tag = element.tagName.toLowerCase();
if ("video" == tag)
{
ProcessVideoElement(element);
}
}
var insertBeforeOriginal = doc.body.insertBefore;
doc.body.insertBefore = function(element, reference)
{
insertBeforeOriginal(element, reference);
var tag = element.tagName.toLowerCase();
if ("video" == tag)
{
ProcessVideoElement(element);
}
}
}
...
code cut out
HI,
I'm dealing with the exact same problem occuring when opening a prettyPhoto gallery...
I have no idea where this "script block" is coming from, but it definitely causes the error.
So, does anyone know anything on this suspicious script block?
Thanks,
aeno
edit:
A little more googling shed some light onto it: The mentioned script block comes from the DivX plugin that's installed in InternetExplorer. Deactivating the DivX plugin suddenly solved the problem and prettyPhoto opens quite smooth :)
Now I have to figure out whether the DivX developers have bug tracker...
Is there anyway to listen to the onload event for a <link> element?
F.ex:
var link = document.createElement('link');
link.rel = 'stylesheet';
link.href = 'styles.css';
link.onload = link.onreadystatechange = function(e) {
console.log(e);
};
This works for <script> elements, but not <link>. Is there another way?
I just need to know when the styles in the external stylesheet has applied to the DOM.
Update:
Would it be an idea to inject a hidden <iframe>, add the <link> to the head and listen for the window.onload event in the iframe? It should trigger when the css is loaded, but it might not guarantee that it's loaded in the top window...
Today, all modern browsers support the onload event on link tags. So I would guard hacks, such as creating an img element and setting the onerror:
if !('onload' in document.createElement('link')) {
imgTag = document.createElement(img);
imgTag.onerror = function() {};
imgTag.src = ...;
}
This should provide a workaround for FF-8 and earlier and old Safari & Chrome versions.
minor update:
As Michael pointed out, there are some browser exceptions for which we always want to apply the hack. In Coffeescript:
isSafari5: ->
!!navigator.userAgent.match(' Safari/') &&
!navigator.userAgent.match(' Chrom') &&
!!navigator.userAgent.match(' Version/5.')
# Webkit: 535.23 and above supports onload on link tags.
isWebkitNoOnloadSupport: ->
[supportedMajor, supportedMinor] = [535, 23]
if (match = navigator.userAgent.match(/\ AppleWebKit\/(\d+)\.(\d+)/))
match.shift()
[major, minor] = [+match[0], +match[1]]
major < supportedMajor || major == supportedMajor && minor < supportedMinor
This is kind of a hack, but if you can edit the CSS, you could add a special style (with no visible effect) that you can listen for using the technique in this post: http://www.west-wind.com/weblog/posts/478985.aspx
You would need an element in the page that has a class or an id that the CSS will affect. When your code detects that its style has changed, the CSS has been loaded.
A hack, as I said :)
The way I did it on Chrome (not tested on other browsers) is to load the CSS using an Image object and catching its onerror event. The thing is that browser does not know is this resource an image or not, so it will try fetching it anyway. However, since it is not an actual image it will trigger onerror handlers.
var css = new Image();
css.onerror = function() {
// method body
}
// Set the url of the CSS. In link case, link.href
// This will make the browser try to fetch the resource.
css.src = url_of_the_css;
Note that if the resource has already been fetched, this fetch request will hit the cache.
E.g. Android browser doesn't support "onload" / "onreadystatechange" events for element: http://pieisgood.org/test/script-link-events/
But it returns:
"onload" in link === true
So, my solution is to detect Android browser from userAgent and then wait for some special css rule in your stylesheet (e.g., reset for "body" margins).
If it's not Android browser and it supports "onload" event- we will use it:
var userAgent = navigator.userAgent,
iChromeBrowser = /CriOS|Chrome/.test(userAgent),
isAndroidBrowser = /Mozilla\/5.0/.test(userAgent) && /Android/.test(userAgent) && /AppleWebKit/.test(userAgent) && !iChromeBrowser;
addCssLink('PATH/NAME.css', function(){
console.log('css is loaded');
});
function addCssLink(href, onload) {
var css = document.createElement("link");
css.setAttribute("rel", "stylesheet");
css.setAttribute("type", "text/css");
css.setAttribute("href", href);
document.head.appendChild(css);
if (onload) {
if (isAndroidBrowser || !("onload" in css)) {
waitForCss({
success: onload
});
} else {
css.onload = onload;
}
}
}
// We will check for css reset for "body" element- if success-> than css is loaded
function waitForCss(params) {
var maxWaitTime = 1000,
stepTime = 50,
alreadyWaitedTime = 0;
function nextStep() {
var startTime = +new Date(),
endTime;
setTimeout(function () {
endTime = +new Date();
alreadyWaitedTime += (endTime - startTime);
if (alreadyWaitedTime >= maxWaitTime) {
params.fail && params.fail();
} else {
// check for style- if no- revoke timer
if (window.getComputedStyle(document.body).marginTop === '0px') {
params.success();
} else {
nextStep();
}
}
}, stepTime);
}
nextStep();
}
Demo: http://codepen.io/malyw/pen/AuCtH
Since you didn't like my hack :) I looked around for some other way and found one by brothercake.
Basically, what is suggested is to get the CSS using AJAX to make the browser cache it and then treat the link load as instantaneous, since the CSS is cached. This will probably not work every single time (since some browsers may have cache turned off, for example), but almost always.
Another way to do this is to check how many style sheets are loaded. For instance:
With "css_filename" the url or filename of the css file, and "callback" a callback function when the css is loaded:
var style_sheets_count=document.styleSheets.length;
var css = document.createElement('link');
css.setAttribute('rel', 'stylesheet');
css.setAttribute('type', 'text/css');
css.setAttribute('href', css_filename);
document.getElementsByTagName('head').item(0).appendChild(css);
include_javascript_wait_for_css(style_sheets_count, callback, new Date().getTime());
function include_javascript_wait_for_css(style_sheets_count, callback, starttime)
/* Wait some time for a style sheet to load. If the time expires or we succeed
* in loading it, call a callback function.
* Enter: style_sheet_count: the original number of style sheets in the
* document. If this changes, we think we finished
* loading the style sheet.
* callback: a function to call when we finish loading.
* starttime: epoch when we started. Used for a timeout. 12/7/11-DWM */
{
var timeout = 10000; // 10 seconds
if (document.styleSheets.length!=style_sheets_count || (new Date().getTime())-starttime>timeout)
callback();
else
window.setTimeout(function(){include_javascript_wait_for_css(style_sheets_count, callback, starttime)}, 50);
}
This trick is borrowed from the xLazyLoader jQuery plugin:
var count = 0;
(function(){
try {
link.sheet.cssRules;
} catch (e) {
if(count++ < 100)
cssTimeout = setTimeout(arguments.callee, 20);
else
console.log('load failed (FF)');
return;
};
if(link.sheet.cssRules && link.sheet.cssRules.length == 0) // fail in chrome?
console.log('load failed (Webkit)');
else
console.log('loaded');
})();
Tested and working locally in FF (3.6.3) and Chrome (linux - 6.0.408.1 dev)
Demo here (note that this won't work for cross-site css loading, as is done in the demo, under FF)
You either need a specific element which style you know, or if you control the CSS file, you can insert a dummy element for this purpose. This code will exactly make your callback run when the css file's content is applied to the DOM.
// dummy element in the html
<div id="cssloaded"></div>
// dummy element in the css
#cssloaded { height:1px; }
// event handler function
function cssOnload(id, callback) {
setTimeout(function listener(){
var el = document.getElementById(id),
comp = el.currentStyle || getComputedStyle(el, null);
if ( comp.height === "1px" )
callback();
else
setTimeout(listener, 50);
}, 50)
}
// attach an onload handler
cssOnload("cssloaded", function(){
alert("ok");
});
If you use this code in the bottom of the document, you can move the el and comp variables outside of the timer in order to get the element once. But if you want to attach the handler somewhere up in the document (like the head), you should leave the code as is.
Note: tested on FF 3+, IE 5.5+, Chrome
The xLazyLoader plugin fails since the cssRules properties are hidden for stylesheets that belong to other domains (breaks the same origin policy). So what you have to do is compare the ownerNode and owningElements.
Here is a thorough explanation of what todo:
http://yearofmoo.com/2011/03/cross-browser-stylesheet-preloading/
// this work in IE 10, 11 and Safari/Chrome/Firefox/Edge
// if you want to use Promise in an non-es6 browser, add an ES6 poly-fill (or rewrite to use a callback)
let fetchStyle = function(url) {
return new Promise((resolve, reject) => {
let link = document.createElement('link');
link.type = 'text/css';
link.rel = 'stylesheet';
link.onload = resolve;
link.href = url;
let headScript = document.querySelector('script');
headScript.parentNode.insertBefore(link, headScript);
});
};
This is a cross-browser solution
// Your css loader
var d = document,
css = d.head.appendChild(d.createElement('link'))
css.rel = 'stylesheet';
css.type = 'text/css';
css.href = "https://unpkg.com/tachyons#4.10.0/css/tachyons.css"
// Add this
if (typeof s.onload != 'undefined') s.onload = myFun;
} else {
var img = d.createElement("img");
img.onerror = function() {
myFun();
d.body.removeChild(img);
}
d.body.appendChild(img);
img.src = src;
}
function myFun() {
/* ..... PUT YOUR CODE HERE ..... */
}
The answer is based on this link that say:
What happens behind the scenes is that the browser tries to load the
CSS in the img element and, because a stylesheet is not a type of
image, the img element throws the onerror event and executes our
function. Thankfully, browsers load the entire CSS file before
determining its not an image and firing the onerror event.
In modern browsers you can do css.onload and add that code as a fallback to cover old browsers back to 2011 when only Opera and Internet Explorer supported the onload event and onreadystatechange respectively.
Note: I have answered here too and it is my duplicate and deserves to be punished for my honesteness :P