title: Firefox Add-ons, How to execute javascript function onLoad?
body: <p>I'm new to Firefox Add-ons. I want to create a simple Firefox add-ons that append HTML element to a page automatically on document Load. Honestly, I want to add additional BBCODE/smiley toolbar to the any existing textarea.</p>
  
  <p>I got an example of xul (xml) file:</p>
  
  <pre><code>  &lt;popup id="contentAreaContextMenu"&gt;
    &lt;!-- some code here --&gt;
   &lt;/popup&gt; 
  
  
  
   &lt;!-- toolbar button --&gt;
   &lt;toolbarpalette id="BrowserToolbarPalette"&gt;
    &lt;!-- some code here --&gt;
   &lt;/toolbarpalette&gt;
  
   &lt;!-- keyboard shortcut --&gt;
   &lt;keyset&gt;
    &lt;!-- some code here --&gt;
   &lt;/keyset&gt;
  </code></pre>
  
  <p>Is that easy to create a toolbar, popup menu or keyboard shortcut using script above.</p>
  
  <p>The thing i just want to know is, what is the XML code to execute javasript function automatically on page load (without execute command from popup, toolbar or keyboard shortcut)???</p>
  
  <p>I hope you understand with my question and everyone who help me i say thank you.</p>