Question

I’m totally new to GreaseMonkey, but I’m trying to make a little script.

// ==UserScript==
// @require       http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js
// ==/UserScript==
(function() {
    $ = unsafeWindow.jQuery;
    alert($); // this gives 'undefined'
}());

Why does the alert give undefined and how to fix this?

UPDATE

I tried this:

(function(){
  //boilerplate greasemonkey to wait until jQuery is defined...
  function GM_wait()
  {
    alert('ok');
    if(typeof unsafeWindow.jQuery == 'undefined')
      window.setTimeout(GM_wait,100);
    else
      unsafeWindow.jQuery(function() { letsJQuery(unsafeWindow.jQuery); });
  }
  GM_wait();

  function letsJQuery($)
  {
    alert($);
  }
})(); 

but this gave me an infinite loop of ok-alerts. Seems like jQuery doesn’t get loaded at all.

Answer 1

Edit: Could it be this?

Perhaps you don’t have a recent enough version of Greasemonkey. It was version 0.8 that added @require. Also, remember that @require is only processed when the script is first installed. If you change the list of required scripts, you need to uninstall it and reinstall it; Greasemonkey downloads the required script once at installation and uses a cached copy thereafter.

---

The GM script could be executing before the page is ready (i.e. before jQuery has initialized). I use this code in my Greasemonkey scripts in order to use jQuery:

(function(){
  //boilerplate greasemonkey to wait until jQuery is defined...
  function GM_wait()
  {
    if(typeof unsafeWindow.jQuery == 'undefined')
      window.setTimeout(GM_wait,100);
    else
      unsafeWindow.jQuery(function() { letsJQuery(unsafeWindow.jQuery); });
  }
  GM_wait();

  function letsJQuery($)
  {
    //whatever
  }
})();