Firefox Extension: Get selected text

Question

I am working on a simple Firefox Extension and I want to get the selected text. I tried this:

var WordCount = {
    /* ... */
    changeSelected: function() {
           


        

Answer 1

Is this a normal Firefox extension or is it a JetPack Firefox extension.

In JetPack it would be

var doc = jetpack.tabs.focused.contentWindow;
if (doc.wrappedJSObject){ //This just checks if Firefox has put a XPCNativeWrapper around it for security
  win = doc.wrappedJSObject;
}

or you can just access the window directly with window.getSelection() like dcaunt suggested