/**
* Only returns true when the external script has been
* loaded in to the DOM.  It uses arguments.callee.caller
* to work out which function is the callback.
*
* @param url {String} URL of external script
* @param obj {String} The name of a function or variable
* within the external script to test for.
* @license: Creative Commons License -
* ShareAlike http://creativecommons.org/licenses/by-sa/3.0/
* @author Remy Sharp / leftlogic.com
*/
function waitingForScript(url, obj) {
	var callback = arguments.callee.caller;
	var args = arguments.callee.caller.arguments;
	var s, ok, timer, doc = document;

  // if the object/function doesn't exist and we've not tried to load it
  // then pull it in and fire the calling function once complete
	if ((typeof window[obj] == "undefined") && !window["loading" + obj]) {
		window["loading" + obj] = true;
		if (!doc.getElementById("_" + obj)) {
			s = doc.createElement("script");
			s.src = url;
			s.id = "_" + obj;
			doc.body.appendChild(s);
		}
		timer = setInterval(function () {
			ok = false;
			try {
				ok = (typeof window[obj] != "undefined");
			}
			catch (e) {
			}
			if (ok) {
				clearInterval(timer);
				callback.apply(this, args);
			}
		}, 10);

    // we're loading in the script now, so we're currently waiting
		return true;
	} else {
		if (typeof window[obj] == "undefined") {
    // object not defined yet, so we're still waiting
			return true;
		} else {
    // it's already loaded
			return false;
		}
	}
}