Hi, I have a Greasemonkey script that processes Google search results. But it's failing in a few instances, when xpath searches (and document body) appear to be empty.

Running the code in Firebug's console works every time. It only fails in a Greasemonkey script. Greasemonkey sees an empty document.body.

I've boiled the problem down to a test, greasemonkey script, below.
I'm using Firefox 3.5.9 and Greasemonkey 0.8.20100408.6 (but earlier versions had the same problem).

Problem:

Greasemonkey sees an empty document.body.

Recipe to Duplicate:

1. Install the Greasemonkey script.
2. Open a new tab or window.
3. Navigate to Google.com (http://www.google.com/).
4. Search on a simple term like "cats".
5. Check Firefox's Error console (Ctrl-shift-J) or Firebug's console. The script will report that document body is empty.
6. Hit refresh. The script will show a good result (document body found).
7. Note that the failure only reliably appears on Google results obtained this way, and on a new tab/window.
8. Turn javascript off globally (javascript.enabled set to false in about:config).
9. Repeat steps 2 thru 5. Only now the Greasemonkey script will work.

It seems that Google javascript is killing the DOM tree for greasemonkey, somehow. I've tried a time-delayed retest and even a programmatic refresh; the script still fails to see the document body.

Test Script:

//
// ==UserScript==
// @name            TROUBLESHOOTING 2 snippets
// @namespace       http://www.google.com/
// @description     For code that has funky misfires and defies standard debugging.
// @include         http://*/*
// ==/UserScript==
//


function LocalMain (sTitle)
{
    var sUserMessage    = '';
  //var sRawHtml        = unsafeWindow.document.body.innerHTML; //-- unsafeWindow makes no difference.
    var sRawHtml        = document.body.innerHTML;
    if (sRawHtml)
    {
        sRawHtml        = sRawHtml.replace (/^\s\s*/, ''). substr (0, 60);
        sUserMessage    = sTitle + ', Doc body = ' + sRawHtml + ' ...';
    }
    else
    {
        sUserMessage    = sTitle + ', Document body seems empty!';
    }


    if (typeof (console) != "undefined")
    {
        console.log  (sUserMessage);
    }
    else
    {
        if (typeof (GM_log) != "undefined")
            GM_log (sUserMessage);
        else
            if (!sRawHtml)
                alert (sUserMessage);
    }
}


LocalMain ('Preload');

window.addEventListener ("load", function() {LocalMain ('After load');}, false);