interaction beetween firefox xul estension and a web page - javascript

I'm writing a firefox xul extension, and I must have an interaction beetween the web page and extension.
Example: If I press a link from the page I want to call a function in the xul extension.
Anyone know if there is a way?
Thanks a lot

Yes, you can do this. You'll need to access page content with the content object.
In your extension code you can select all links and then add an eventListener:
allLinks = content.document.getElementsByTagName("a"),
for (var i=0, il=allLinks.length; i<il; i++) {
elm = allLinks[i];
elm.addEventListener("click", nowclicked, false);
}
And then your event listener would look something like:
nowclicked : function () {
alert("a linked was clicked!");
}
If you need a working example, I've modified the Link Target Finder extension by Robert Nyman to add an alert when links are clicked. The modified code is in linkTargetFinder.js.

See MDN example for Sending data from unprivileged document to chrome document.
Basically, in your chrome code you have to add a listener:
// The last value is a Mozilla-specific value to indicate untrusted content is allowed to trigger the event.
document.addEventListener("MyExtensionEvent", function(e) {myExtension.myListener(e);}, false, true);
and fire the event from content script. Note that document in the following is the contentDocument not XulDocument
var evt = document.createEvent("Events");
evt.initEvent("MyExtensionEvent", true, false);
element.dispatchEvent(evt);

Related

How to get the element from a view-source: page?

I have made a small Chrome extension which has a click event listener that captures the element and then it gives the xpath.
But this is not capturing anything on a view-source: page.
Is there any way by which I can capture the element from view-source: page in JavaScript?
I am trying with this code on my content page:
document.addEventListener('click', function xyz(e){
e.preventDefault();
//alert(e);
var target = e.target || event.srcElement;
var attributes = Array.prototype.slice.call(target.attributes).map(function(i) {
return [String(i.name)+": "+String(i.value)]
})
alert(attributes);
prompt("xpath1 :",getPathTo(target));
chrome.runtime.sendMessage({method:"captureElement",data:attributes});
},true)
There is nothing you can do, you can't interact with those pages.
Extensions cannot get access to view-source: protocol pages (it's not a supported scheme), so you can't inject a content script in them at all, even with "<all_urls>" filter.

Which XUL element to use when a url is entered and loaded for calling JS?

I am developing a Firefox add-on using XUL Overlay and want to call a specific js when the current page loads after entering the URL. I want to know which XUL element would be affected and should be used to call said JS, such as page or tab or window or ??? Also, which event would be best for the element? Or is my logic wrong?
Also,the js's function is to record tab title and/or url so i need to know when to call js and with corresponding event. Thanks.. :)
The XUL element you should be watching is the tabbrowser. In the browser window (which means also in overlays applied to the browser window) it can be accessed via the global gBrowser variable. If you want to know when a page finishes loading you can listen to the DOMContentLoaded event. Something like this (untested code):
// Declare an own namespace for extension's functions to avoid
// name conflicts with other extensions.
var MyExtension = {};
MyExtension.init = function()
{
gBrowser.addEventListener("DOMContentLoaded", MyExtension.onPageLoad, false);
};
MyExtension.onPageLoad = function(event)
{
// Get the document that loaded
var doc = event.originalTarget;
// Ignore frames that load
if (doc.defaultView != doc.defaultView.parent)
return;
// Ignore if this isn't the active tab
var browser = gBrowser.getBrowserForDocument(doc);
if (browser != gBrowser.selectedBrowser)
return;
alert("Page loaded in current tab: " + doc.defaultView.location.href);
};
// Wait for the browser window to finish loading before adding event listeners
window.addEventListener("load", MyExtension.init, false);
If you want to get notified earlier, when the address displayed in the URL bar changes, you can use a progress listener instead. You want to implement the method onLocationChange of the progress listener and leave the other methods empty. Note that this method is also called when the user switches to a different tab (this also causes a location bar change). Also: the parameter aURI passed to onLocationChange is an nsIURI instance. If you want the URL as a string you should look at aURI.spec.

Detecting the onload event of a window opened with window.open

window.popup = window.open($(this).attr('href'), 'Ad', 'left=20,top=20,width=500,height=500,toolbar=1,resizable=0');
$(window.popup).onload = function()
{
alert("Popup has loaded a page");
};
This doesn't work in any browser I've tried it with (IE, Firefox, Chrome). How can I detect when a page is loaded in the window (like an iframe onload)?
var myPopup = window.open(...);
myPopup.addEventListener('load', myFunction, false);
If you care about IE, use the following as the second line instead:
myPopup[myPopup.addEventListener ? 'addEventListener' : 'attachEvent'](
(myPopup.attachEvent ? 'on' : '') + 'load', myFunction, false
);
As you can see, supporting IE is quite cumbersome and should be avoided if possible. I mean, if you need to support IE because of your audience, by all means, do so.
If the pop-up's document is from a different domain, this is simply not possible.
Update April 2015: I was wrong about this: if you own both domains, you can use window.postMessage and the message event in pretty much all browsers that are relevant today.
If not, there's still no way you'll be able to make this work cross-browser without some help from the document being loaded into the pop-up. You need to be able to detect a change in the pop-up that occurs once it has loaded, which could be a variable that JavaScript in the pop-up page sets when it handles its own load event, or if you have some control of it you could add a call to a function in the opener.
As noted at Detecting the onload event of a window opened with window.open, the following solution is ideal:
/* Internet Explorer will throw an error on one of the two statements, Firefox on the other one of the two. */
(function(ow) {
ow.addEventListener("load", function() { alert("loaded"); }, false);
ow.attachEvent("onload", function() { alert("loaded"); }, false);
})(window.open(prompt("Where are you going today?", location.href), "snapDown"));
Other comments and answers perpetrate several erroneous misconceptions as explained below.
The following script demonstrates the fickleness of defining onload. Apply the script to a "fast loading" location for the window being opened, such as one with the file: scheme and compare this to a "slow" location to see the problem: it is possible to see either onload message or none at all (by reloading a loaded page all 3 variations can be seen). It is also assumed that the page being loaded itself does not define an onload event which would compound the problem.
The onload definitions are evidently not "inside pop-up document markup":
var popup = window.open(location.href, "snapDown");
popup.onload = function() { alert("message one"); };
alert("message 1 maybe too soon\n" + popup.onload);
popup.onload = function() { alert("message two"); };
alert("message 2 maybe too late\n" + popup.onload);
What you can do:
open a window with a "foreign" URL
on that window's address bar enter a javascript: URI -- the code will run with the same privileges as the domain of the "foreign" URL
The javascript: URI may need to be bookmarked if typing it in the address bar has no effect (may be the case with some browsers released around 2012)
Thus any page, well almost, irregardless of origin, can be modified like:
if(confirm("wipe out links & anchors?\n" + document.body.innerHTML))
void(document.body.innerHTML=document.body.innerHTML.replace(/<a /g,"< a "))
Well, almost:
jar:file:///usr/lib/firefox/omni.ja!/chrome/toolkit/content/global/aboutSupport.xhtml, Mozilla Firefox's troubleshooting page and other Jar archives are exceptions.
As another example, to routinely disable Google's usurping of target hits, change its rwt function with the following URI:
javascript: void(rwt = function(unusurpURL) { return unusurpURL; })
(Optionally Bookmark the above as e.g. "Spay Google" ("neutralize Google"?)
This bookmark is then clicked before any Google hits are clicked, so bookmarks of any of those hits are clean and not the mongrelized perverted aberrations that Google made of them.
Tests done with Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:11.0) Gecko/20100101 Firefox/11.0 UA string.
It should be noted that addEventListener in Firefox only has a non-standard fourth, boolean parameter, which if true allows untrusted content triggers to be instantiated for foreign pages.
Reference:
element.addEventListener | Document Object Model (DOM) | MDN:
Interaction between privileged and non-privileged pages | Code snippets | MDN:
This did the trick for me; full example:
HTML:
Click for my popup on same domain
Javascript:
(function(){
var doc = document;
jQuery('.import').click(function(e){
e.preventDefault();
window.popup = window.open(jQuery(this).attr('href'), 'importwindow', 'width=500, height=200, top=100, left=200, toolbar=1');
window.popup.onload = function() {
window.popup.onbeforeunload = function(){
doc.location.reload(true); //will refresh page after popup close
}
}
});
})();
onload event handler must be inside popup's HTML <body> markup.
First of all, when your first initial window is loaded, it is cached. Therefore, when creating a new window from the first window, the contents of the new window are not loaded from the server, but are loaded from the cache. Consequently, no onload event occurs when you create the new window.
However, in this case, an onpageshow event occurs. It always occurs after the onload event and even when the page is loaded from cache. Plus, it now supported by all major browsers.
window.popup = window.open($(this).attr('href'), 'Ad', 'left=20,top=20,width=500,height=500,toolbar=1,resizable=0');
$(window.popup).onpageshow = function() {
alert("Popup has loaded a page");
};
The w3school website elaborates more on this:
The onpageshow event is similar to the onload event, except that it occurs after the onload event when the page first loads. Also, the onpageshow event occurs every time the page is loaded, whereas the onload event does not occur when the page is loaded from the cache.
The core problem seems to be you are opening a window to show a page whose content is already cached in the browser. Therefore no loading happens and therefore no load-event happens.
One possibility could be to use the 'pageshow' -event instead, as described in:
https://support.microsoft.com/en-us/help/3011939/onload-event-does-not-occur-when-clicking-the-back-button-to-a-previou
Simple solution:
new_window = window.open(...);
new_window.document.write('<body onload="console.log(1);console.log(2);></body>');

Communication between firefox extension and page javascript

I am developing a web-based javascript/html application with a sister firefox-extension.
The application's page-javascript performs a few XHR calls immediately after page-load, in order to bring in and display all the content that the page requires.
Is there a way, without polling the DOM, that my extension can know that the page's initialisation procedures are complete?
Interesting question indeed..
I've just found out through this post on MozillaZine's forum an easy way to accomplish this. The technique basically consists in defining a custom DOM element within the web page, filling it with some arbitrary attributes, and then using it as the target of a custom event. The event can than be captured and used to pass values from the webpage to the extension.
Web page (assumes jquery is available)
<script type="text/javascript">
$(document).ready(function(){
$.get("http://mywebsite.net/ajax.php",function(data){
//[...]process data
//define a custom element and append it to the document
var element = document.createElement("MyExtensionDataElement");
element.setAttribute("application_state", "ready");
document.documentElement.appendChild(element);
//create a custom event and dispatch it
// using the custom element as its target
var ev = document.createEvent("Events");
ev.initEvent("MyExtensionEvent", true, false);
element.dispatchEvent(ev);
});
});
</script>
Chrome code:
function myListener(e) {
alert("data:" + e.target.getAttribute("application_state"));
}
function on_specialpage_load(event) {
if (event.originalTarget instanceof HTMLDocument &&
event.originalTarget.location.href == "http://mywebsite.net/myspecialpage.html") {
var doc=event.originalTarget;
doc.addEventListener("MyExtensionEvent", myListener, false, true);
}
}
gBrowser.addEventListener("DOMContentLoaded",on_specialpage_load,false);
Notice that doc.addEventListener has a fourth parameter, indicating that it will accept events coming from untrusted code. However you can add this event listener selectively, so that only trusted pages from your site will be able to pass values to the extension.
You could hook into the XMLHttpRequest object from your extension and monitor the requests, similar to what this GreaseMonkey script does (description). Add a wrapper to onreadystatechange in the same way he's added a wrapper to open which notifies the extension when complete. Probably also want some code which makes sure you're only doing this when visiting your own page.
Firebug does similar stuff for its Net panel, the codebase for that is a bit more intimidating though :) I also had a look at the Firebug Lite watchXHR function, but that code is a bit too cunning for me, if you can work it out let me know.

In XUL, how do I know a browser-tag has finished loading?

I'm developing a firefox extension based on this tutorial which is a FF 2.0 extension (second part of the tutorial is at this url)
The main thing that is important is that it uses
<iframe id="contentview" src="http://www.ibm.com/developerworks/web" flex="2"/>
In the backend code, when clicking the GO button, this happens:
contentview.contentDocument.location.href = urlbox.value;
//Use Firefox XPath to get the raw text of the document
var doctext = contentview.contentDocument.evaluate(
"string(.)", document, null, XPathResult.STRING_TYPE, null).stringValue;
I get an error with the xpath, but that's not my question. The issue I have with FF 3.0 is that the contentDocument value refers to the old site loaded, not to the one loaded by the href-change.
So my question is: how can I create a similar window, but be notified someone when the loaded document is complete, so I can access its DOM?
Updated:
first you need to handle the load event of the window then you add an event listener to the iframe element
window.addEventListener("load",Listen,false);
function Listen()
{
var frame = document.getElementById("contentview");
frame.addEventListener("DOMContentLoaded", DomLoadedEventHandler, true);
}
function DomLoadedEventHandler() {
var frame = document.getElementById("contentview");
alert(frame.contentDocument.location.href);
}
replace "DomLoadedEventHandler" with your event handler name.
I recommend that you take a look at the official site of Mozilla to learn everything about Firefox extensions
http://developer.mozilla.com

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