On Page Load: Difference between revisions

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{{extdev}}
#redirect [[On page load]]
 
This article is for XUL/Javascript developers who want to have their code executed each time a new page is loaded in browser/mail.
 
==Creating an overlay==
First, you need to create an overlay to one (or more, depending on which applications you target) of the following XUL documents:
{| border="1" cellpadding="5" rules="all"
! Application !! URI to overlay
|-
| Firefox || <code>chrome://browser/content/browser.xul</code>
|-
| Thunderbird and Mozilla Mail || <code>chrome://messenger/content/messenger.xul</code>
|-
| Navigator from the Mozilla Suite || <code>chrome://navigator/content/navigator.xul</code>
|}
 
==Attaching a script==
Attach a script to your overlay, and add a <code>load</code> event listener to <code>appcontent</code> element (browsers) or <code>messagepane</code> (mail) by putting this code in the script:
 
<pre>window.addEventListener("load", function() { myExtension.init(); }, false);
 
var myExtension = {
  init: function() {
    var appcontent = document.getElementById("appcontent");  // browser
    if(appcontent)
      appcontent.addEventListener("load", this.onPageLoad, true);
    var messagepane = document.getElementById("messagepane"); // mail
    if(messagepane)
      messagepane.addEventListener("load", this.onPageLoad, true);
  },
 
  onPageLoad: function(aEvent) {
    var doc = aEvent.originalTarget; // doc is document that triggered "onload" event
    // do something with the loaded page.
    // doc.location is a Location object (see below for a link).
    // You can use it to make your code executed on certain pages only.
    if(doc.location.href.search("forum") > -1)
      alert("a forum page is loaded");
  }
}
</pre>
 
==References==
* See Chris Neale's URIid extension for a working example.
* If you need to have a more complicated listener (not just onload), use [[Dev : Extensions : Example Code : Progress Listeners|progress listeners]].
* [http://xulplanet.com/references/objref/Location.html Location object]
 
[[Category:Development|On Tab Load]] [[Category:Example code|On Tab Load]]

Latest revision as of 20:26, 6 December 2005

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