Button is always null even after window is loaded [duplicate] - javascript

I'm trying to attach an eventlistener to the "click" event of a button on a page in an IFrame. The page in the iframe belongs to the same domain as the parent window.
window.frames["iframe_Id"].document.getElementById("button_id").addEventListener("click",functionToRun,false);
The above sample is not working for me. It could just be a a syntax error in my actual code but I wanted to see if this is the general idea.
Note: I found plenty of examples on adding the click event to the entire Iframe but I'm not sure it works the same for buttons within the Iframe.

Using jQuery:
$("#iframe_Id").contents("#button_id").click(functionToRun);
Or without jQuery:
document.getElementById("iframe_Id").contentWindow.document.getElementById("button_id").addEventListener("click", functionToRun, false);
This will only work if the iframe meets the same origin policy.

window.frames is an array-like object, so its elements can be accessed by indexes only.
You should loop through them, and check their id, e.g.:
var frame; for(i = 0; i < frames.length; i++) {
frame = frames[i];
if (frame.id === 'iframe_id') {
frame.document
.getElementById("button_id")
.addEventListener("click",functionToRun,false);
}
}

Have you tried executing the event in the "capturing" vs. "bubbling" phase?
document.getElementById("iframe_Id")
.document.addEventListener("click", functionToRun, true);
Note the true instead of false as the final parameter.

window.frames["iframe_Id"].contentWindow.document.getElementById("button_id").addEventListener("click",functionToRun,false);
^
The contentWindow property.
From the DOM iframe element, scripts can get access to the window
object of the included HTML page via the contentWindow property.

Related

Why is iframe.contentWindow == null?

I use the following code to dynamically create an iframe.
var iframe_jquery = $("<iframe>")
.addClass("foo")
.appendTo(container); // container is a jQuery object containing a <div> which already exists
Then, I want to access its contentWindow, but it's null:
var iframe = iframe_jquery.get(0);
if (iframe){ // iFrame exists
console.log(iframe.contentWindow); // Prints "null"
var doc = iframe.contentWindow.document; // NullpointerException
}
So I thought: "Maybe the iframe isn't ready yet?" So I tried:
iframe_jquery.ready(function(){
var iframe = iframe_jquery.get(0);
console.log(iframe.contentWindow); // Prints "null"
var doc = iframe.contentWindow.document; // NullpointerException
});
Same result.
What's wrong?
I had this problem last week while playing with iframes (building an rtf editor), and yeah it's not ready yet.
I thought if I put it in a .ready(), it would work, but .ready() is when the DOM is ready, not when the iframe has loaded its contents, so I ended up wrapping my code with jQuery .load().
So try this:
$(function () {
$("#myiframe").load(function () {
frames["myframe"].document.body.innerHTML = htmlValue;
});
});
Hope this helps
The problem is that your <iframe> won't be "real" until it's really added to the actual DOM for the page. Here is a fiddle to demonstrate..
Depending on the browser, accessing the document or an <iframe> may vary.
Here is an example of how to handle it:
if (iframe.contentDocument) // FF Chrome
doc = iframe.contentDocument;
else if ( iframe.contentWindow ) // IE
doc = iframe.contentWindow.document;
You can also make a function that will be executed when the iframe has finished loading by setting it's onload attribute.
Bookmarklet version
Just out of curiosity I thought I'd put this together. Remembering that iframes and load events don't play well together on different browsers (mainly older, falling apart, should-be-dead browsers)... plus not being entirely sure how jQuery gets around this problem... my brain decided that this would be better supported (whether it is or not is neither here nor there):
$(function(){
/// bind a listener for the bespoke iframeload event
$(window).bind('iframeload', function(){
/// access the contents of the iframe using jQuery notation
iframe.show().contents().find('body').html('hello');
});
/// create your iframe
var iframe = $('<iframe />')
/// by forcing our iframe to evaluate javascript in the path, we know when it's ready
.attr('src', 'javascript:(function(){try{p=window.parent;p.jQuery(p).trigger(\'iframeload\');}catch(ee){};})();')
/// insert the iframe into the live DOM
.appendTo('body');
});
The reason for taking this approach is that it is normally far better to trigger your load event from inside the iframe itself. But this means having a proper document loaded in to the iframe, so for dynamic iframes this is a little tedious. This is kind of a mixture between having a document loaded, and not.
The above works on everything I have tested so far - and yes you are correct - it is a little ridiculous, non-future-proof and propably other things that have negative connotations ;)
One positive thing I'll say about this post is that introduces the use of .contents() to access the document of the iframe, which is at least a little bit useful...

Is there any way to get "global" events when working with nested iframes?

My problem is I need to capture a keypress but at any given time the user can be inside of an iframe inside of an iframe inside of an iframe.
At first, I thought I could just put the listener on document but that doesn't work if the user is inside of one of those iframes.
Next I thought of attaching the handler to window but ie doesn't support attaching event handlers to window. I'm not even sure if that would work though or it would be the same problem as with document.
Next, I thought I could just go through all the iframes and add individual handlers there but eventually realized that wouldn't work because the iframe doesn't have any html in the dom so there is no way to access iframes nested in it.
One other possible solution is to go to the js of all the iframes and add this code manually but that is way too extreme.
Any other ideas?
I keep answering my own questions but oh well. If you come across this problem I figured out the answer. This uses jquery but you could port it to straight js if you had to.
var myFunction = function () {
alert("hello world");
};
var $myWindow = $(myWindow /*dom object*/);
$myWindow.bind("mouseover", myFunction);
var getNested_iframes = function (document_element) {
$.each(document_element.find("iframe"), function () {
var iframeDocument = $(this).get(0).contentWindow.document; // may need to change this depending on browser
iframeDocument.onkeyup = myFunction;
getNested_iframes($(iframeDocument));
});
}
getNested_iframes($myWindow);

Event when iframe finishes loading [duplicate]

I need to execute a callback when an IFRAME has finished loading. I have no control over the content in the IFRAME, so I can't fire the callback from there.
This IFRAME is programmaticly created, and I need to pass its data as a variable in the callback, as well as destroy the iframe.
Any ideas?
EDIT:
Here is what I have now:
function xssRequest(url, callback)
{
var iFrameObj = document.createElement('IFRAME');
iFrameObj.src = url;
document.body.appendChild(iFrameObj);
$(iFrameObj).load(function()
{
document.body.removeChild(iFrameObj);
callback(iFrameObj.innerHTML);
});
}
This callsback before the iFrame has loaded, so the callback has no data returned.
First up, going by the function name xssRequest it sounds like you're trying cross site request - which if that's right, you're not going to be able to read the contents of the iframe.
On the other hand, if the iframe's URL is on your domain you can access the body, but I've found that if I use a timeout to remove the iframe the callback works fine:
// possibly excessive use of jQuery - but I've got a live working example in production
$('#myUniqueID').load(function () {
if (typeof callback == 'function') {
callback($('body', this.contentWindow.document).html());
}
setTimeout(function () {$('#frameId').remove();}, 50);
});
I am using jQuery and surprisingly this seems to load as I just tested and loaded a heavy page and I didn't get the alert for a few seconds until I saw the iframe load:
$('#the_iframe').load(function(){
alert('loaded!');
});
So if you don't want to use jQuery take a look at their source code and see if this function behaves differently with iframe DOM elements, I will look at it myself later as I am interested and post here. Also I only tested in the latest chrome.
I have had to do this in cases where documents such as word docs and pdfs were being streamed to the iframe and found a solution that works pretty well. The key is handling the onreadystatechanged event on the iframe.
Lets say the name of your frame is "myIframe". First somewhere in your code startup (I do it inline any where after the iframe) add something like this to register the event handler:
document.getElementById('myIframe').onreadystatechange = MyIframeReadyStateChanged;
I was not able to use an onreadystatechage attribute on the iframe, I can't remember why, but the app had to work in IE 7 and Safari 3, so that may of been a factor.
Here is an example of a how to get the complete state:
function MyIframeReadyStateChanged()
{
if(document.getElementById('myIframe').readyState == 'complete')
{
// Do your complete stuff here.
}
}
The innerHTML of your iframe is blank because your iframe tag doesn't surround any content in the parent document. In order to get the content from the page referred to by the iframe's src attribute, you need to access the iframe's contentDocument property. An exception will be thrown if the src is from a different domain though. This is a security feature that prevents you from executing arbitrary JavaScript on someone else's page, which would create a cross-site scripting vulnerability. Here is some example code the illustrates what I'm talking about:
<script src="http://prototypejs.org/assets/2009/8/31/prototype.js" type="text/javascript"></script>
<h1>Parent</h1>
<script type="text/javascript">
function on_load(iframe) {
try {
// Displays the first 50 chars in the innerHTML of the
// body of the page that the iframe is showing.
// EDIT 2012-04-17: for wider support, fallback to contentWindow.document
var doc = iframe.contentDocument || iframe.contentWindow.document;
alert(doc.body.innerHTML.substring(0, 50));
} catch (e) {
// This can happen if the src of the iframe is
// on another domain
alert('exception: ' + e);
}
}
</script>
<iframe id="child" src="iframe_content.html" onload="on_load(this)"></iframe>
To further the example, try using this as the content of the iframe:
<h1>Child</h1>
Google
<p>Use the preceeding link to change the src of the iframe
to see what happens when the src domain is different from
that of the parent page</p>
I wanted to hide the waiting spinner div when the i frame content is fully loaded on IE, i tried literally every solution mentioned in Stackoverflow.Com, but with nothing worked as i wanted.
Then i had an idea, that when the i frame content is fully loaded, the $(Window ) load event might be fired. And that exactly what happened. So, i wrote this small script, and worked like magic:
$(window).load(function () {
//alert("Done window ready ");
var lblWait = document.getElementById("lblWait");
if (lblWait != null ) {
lblWait.style.visibility = "false";
document.getElementById("divWait").style.display = "none";
}
});
Hope this helps.
This function will run your callback function immediately if the iFrame is already loaded or wait until the iFrame is completely loaded.
This also addresses the following issues:
Chrome initializes every iFrame with an about:blank page which will have readyState == "complete". Later, it will replace `about:blank with the actual iframe src value. So, the initial value of readyState will not represent the readyState of your actual iFrame. Therefore, besides checking for readyState value, this function also addresses the about:blank issue.
DOMContentLoaded event doesn't work with iFrame. So it uses the load event for running the callback function if iFrame isn't already loaded. The load event is equivalent to readyState == "complete" which has been used to check whether iFrame is already loaded. So, in any scenario, the callback function will run after iFrame is fully loaded.
iFrame src can have redirects and therefore load a page different from the original src url. This function will also work in that scenario.
Pass in your callback function that you want to run when the iFrame finishes loading and the <iframe> element to this function:
function iframeReady(callback, iframeElement) {
const iframeWindow = iframeElement.contentWindow;
if ((iframeElement.src == "about:blank" || (iframeElement.src != "about:blank" && iframeWindow.location.href != "about:blank")) && iframeWindow.document.readyState == "complete") {
callback();
} else {
iframeWindow.addEventListener("load", callback);
}
}
I had a similar problem as you. What I did is that I use something called jQuery. What you then do in the javascript code is this:
$(function(){ //this is regular jQuery code. It waits for the dom to load fully the first time you open the page.
$("#myIframeId").load(function(){
callback($("#myIframeId").html());
$("#myIframeId").remove();
});
});
It seems as you delete you iFrame before you grab the html from it. Now, I do see a problem with that :p
Hope this helps :).
I have a similar code in my projects that works fine.
Adapting my code to your function, a solution could be the following:
function xssRequest(url, callback)
{
var iFrameObj = document.createElement('IFRAME');
iFrameObj.id = 'myUniqueID';
document.body.appendChild(iFrameObj);
iFrameObj.src = url;
$(iFrameObj).load(function()
{
callback(window['myUniqueID'].document.body.innerHTML);
document.body.removeChild(iFrameObj);
});
}
Maybe you have an empty innerHTML because (one or both causes):
1. you should use it against the body element
2. you have removed the iframe from the your page DOM
I think the load event is right.
What is not right is the way you use to retreive the content from iframe content dom.
What you need is the html of the page loaded in the iframe not the html of the iframe object.
What you have to do is to access the content document with iFrameObj.contentDocument.
This returns the dom of the page loaded inside the iframe, if it is on the same domain of the current page.
I would retreive the content before removing the iframe.
I've tested in firefox and opera.
Then i think you can retreive your data with $(childDom).html() or $(childDom).find('some selector') ...
I've had exactly the same problem in the past and the only way I found to fix it was to add the callback into the iframe page. Of course that only works when you have control over the iframe content.
Using onload attrbute will solve your problem.
Here is an example.
function a() {
alert("Your iframe has been loaded");
}
<iframe src="https://stackoverflow.com" onload="a()"></iframe>
Is this what you want?
Click here for more information.

Persistent variable on iframe?

I have a <div> being dynamically created, and it contains an <iframe>. The <iframe> may close itself, at which point the <div> is removed.
So far I have:
var div = document.createElement('div'), ifr = document.createElement('iframe');
// some styles and stuff here, including ifr.src
ifr.contentWindow.container = div; // Note that domains are the same
// within the iframe's code, possibly a "close" link or after completing an operation
container.parentNode.removeChild(container);
It works. But only if the page within the iframe is the one that was there to start with. If a link is clicked to another page, window.container is no longer defined.
I know I can use window.name to store data persistent to a window, but that it limited to data that can be serialised. To my knowledge, you can't serialise a DOM node, other than by assigning it an ID and storing that. I would like to avoid such arbitrary IDs, so if anyone can suggest a better solution I would be very grateful.
Use this code:
//At the frame:
var parentFrames = parent.document.getElementsByTagName("iframe");
for(var i=parentFrames.length-1; i>=0; i--){
if(parentFrames[i].contentWindow == window) {
parentFrames[i].parentNode.removeChild(parentFrames[i]); //Removes frame
//Add an extra `.parent` at each side of the expression to remove the `div`.
break;
}
}
Pages loaded into your <iframe> can use "window.parent" to get to the containing page. Thus, instead of keeping some "magic" reference in the <iframe>, keep it on the containing page and have the "child" pages look for it.
function closeMe() { // inside the iframe page
window.parent.frameContainer.removeChild(window.parent.removableFrame);
}
In addition to "parent", the "top" property of "window" references the top-most context when there's a chain of windows (frames) longer than just one step (so, an <iframe> in an <iframe> etc).

Javascript callback when IFRAME is finished loading?

I need to execute a callback when an IFRAME has finished loading. I have no control over the content in the IFRAME, so I can't fire the callback from there.
This IFRAME is programmaticly created, and I need to pass its data as a variable in the callback, as well as destroy the iframe.
Any ideas?
EDIT:
Here is what I have now:
function xssRequest(url, callback)
{
var iFrameObj = document.createElement('IFRAME');
iFrameObj.src = url;
document.body.appendChild(iFrameObj);
$(iFrameObj).load(function()
{
document.body.removeChild(iFrameObj);
callback(iFrameObj.innerHTML);
});
}
This callsback before the iFrame has loaded, so the callback has no data returned.
First up, going by the function name xssRequest it sounds like you're trying cross site request - which if that's right, you're not going to be able to read the contents of the iframe.
On the other hand, if the iframe's URL is on your domain you can access the body, but I've found that if I use a timeout to remove the iframe the callback works fine:
// possibly excessive use of jQuery - but I've got a live working example in production
$('#myUniqueID').load(function () {
if (typeof callback == 'function') {
callback($('body', this.contentWindow.document).html());
}
setTimeout(function () {$('#frameId').remove();}, 50);
});
I am using jQuery and surprisingly this seems to load as I just tested and loaded a heavy page and I didn't get the alert for a few seconds until I saw the iframe load:
$('#the_iframe').load(function(){
alert('loaded!');
});
So if you don't want to use jQuery take a look at their source code and see if this function behaves differently with iframe DOM elements, I will look at it myself later as I am interested and post here. Also I only tested in the latest chrome.
I have had to do this in cases where documents such as word docs and pdfs were being streamed to the iframe and found a solution that works pretty well. The key is handling the onreadystatechanged event on the iframe.
Lets say the name of your frame is "myIframe". First somewhere in your code startup (I do it inline any where after the iframe) add something like this to register the event handler:
document.getElementById('myIframe').onreadystatechange = MyIframeReadyStateChanged;
I was not able to use an onreadystatechage attribute on the iframe, I can't remember why, but the app had to work in IE 7 and Safari 3, so that may of been a factor.
Here is an example of a how to get the complete state:
function MyIframeReadyStateChanged()
{
if(document.getElementById('myIframe').readyState == 'complete')
{
// Do your complete stuff here.
}
}
The innerHTML of your iframe is blank because your iframe tag doesn't surround any content in the parent document. In order to get the content from the page referred to by the iframe's src attribute, you need to access the iframe's contentDocument property. An exception will be thrown if the src is from a different domain though. This is a security feature that prevents you from executing arbitrary JavaScript on someone else's page, which would create a cross-site scripting vulnerability. Here is some example code the illustrates what I'm talking about:
<script src="http://prototypejs.org/assets/2009/8/31/prototype.js" type="text/javascript"></script>
<h1>Parent</h1>
<script type="text/javascript">
function on_load(iframe) {
try {
// Displays the first 50 chars in the innerHTML of the
// body of the page that the iframe is showing.
// EDIT 2012-04-17: for wider support, fallback to contentWindow.document
var doc = iframe.contentDocument || iframe.contentWindow.document;
alert(doc.body.innerHTML.substring(0, 50));
} catch (e) {
// This can happen if the src of the iframe is
// on another domain
alert('exception: ' + e);
}
}
</script>
<iframe id="child" src="iframe_content.html" onload="on_load(this)"></iframe>
To further the example, try using this as the content of the iframe:
<h1>Child</h1>
Google
<p>Use the preceeding link to change the src of the iframe
to see what happens when the src domain is different from
that of the parent page</p>
I wanted to hide the waiting spinner div when the i frame content is fully loaded on IE, i tried literally every solution mentioned in Stackoverflow.Com, but with nothing worked as i wanted.
Then i had an idea, that when the i frame content is fully loaded, the $(Window ) load event might be fired. And that exactly what happened. So, i wrote this small script, and worked like magic:
$(window).load(function () {
//alert("Done window ready ");
var lblWait = document.getElementById("lblWait");
if (lblWait != null ) {
lblWait.style.visibility = "false";
document.getElementById("divWait").style.display = "none";
}
});
Hope this helps.
This function will run your callback function immediately if the iFrame is already loaded or wait until the iFrame is completely loaded.
This also addresses the following issues:
Chrome initializes every iFrame with an about:blank page which will have readyState == "complete". Later, it will replace `about:blank with the actual iframe src value. So, the initial value of readyState will not represent the readyState of your actual iFrame. Therefore, besides checking for readyState value, this function also addresses the about:blank issue.
DOMContentLoaded event doesn't work with iFrame. So it uses the load event for running the callback function if iFrame isn't already loaded. The load event is equivalent to readyState == "complete" which has been used to check whether iFrame is already loaded. So, in any scenario, the callback function will run after iFrame is fully loaded.
iFrame src can have redirects and therefore load a page different from the original src url. This function will also work in that scenario.
Pass in your callback function that you want to run when the iFrame finishes loading and the <iframe> element to this function:
function iframeReady(callback, iframeElement) {
const iframeWindow = iframeElement.contentWindow;
if ((iframeElement.src == "about:blank" || (iframeElement.src != "about:blank" && iframeWindow.location.href != "about:blank")) && iframeWindow.document.readyState == "complete") {
callback();
} else {
iframeWindow.addEventListener("load", callback);
}
}
I had a similar problem as you. What I did is that I use something called jQuery. What you then do in the javascript code is this:
$(function(){ //this is regular jQuery code. It waits for the dom to load fully the first time you open the page.
$("#myIframeId").load(function(){
callback($("#myIframeId").html());
$("#myIframeId").remove();
});
});
It seems as you delete you iFrame before you grab the html from it. Now, I do see a problem with that :p
Hope this helps :).
I have a similar code in my projects that works fine.
Adapting my code to your function, a solution could be the following:
function xssRequest(url, callback)
{
var iFrameObj = document.createElement('IFRAME');
iFrameObj.id = 'myUniqueID';
document.body.appendChild(iFrameObj);
iFrameObj.src = url;
$(iFrameObj).load(function()
{
callback(window['myUniqueID'].document.body.innerHTML);
document.body.removeChild(iFrameObj);
});
}
Maybe you have an empty innerHTML because (one or both causes):
1. you should use it against the body element
2. you have removed the iframe from the your page DOM
I think the load event is right.
What is not right is the way you use to retreive the content from iframe content dom.
What you need is the html of the page loaded in the iframe not the html of the iframe object.
What you have to do is to access the content document with iFrameObj.contentDocument.
This returns the dom of the page loaded inside the iframe, if it is on the same domain of the current page.
I would retreive the content before removing the iframe.
I've tested in firefox and opera.
Then i think you can retreive your data with $(childDom).html() or $(childDom).find('some selector') ...
I've had exactly the same problem in the past and the only way I found to fix it was to add the callback into the iframe page. Of course that only works when you have control over the iframe content.
Using onload attrbute will solve your problem.
Here is an example.
function a() {
alert("Your iframe has been loaded");
}
<iframe src="https://stackoverflow.com" onload="a()"></iframe>
Is this what you want?
Click here for more information.

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