Firefox addon, accessing selection object via javascript

the javascript file contains this code:

function getSelected(win) {
    sel = win.getSelection();
    alert(sel);
}
开发者_开发问答

The browser.xul file contains this:

<popup id="contentAreaContextMenu">
  <menuitem id="selection" label="Select text" accesskey="S" 
   oncommand="getSelected(window);"/>
</popup> 

The alert is blank, why?

The window object you are using in the getSelection function is the browser's window, not the document's window. You probably need to use content instead:

function getSelected() {
    var sel = content.getSelection();
    alert(sel);
}

Check this resources for more info:

• Firefox Extension: Get selected text
• http://groups.google.com/group/mozilla.dev.extensions/browse_thread/thread/2d106d26d8592bff?pli=1 (The Mozilla page that he points to is really useful)