code: function create_script_load_listener(elem,registry_item,flag,onload) {
  		elem.onload = elem.onreadystatechange = function() {
  			if ((elem.readyState && elem.readyState != "complete" && elem.readyState != "loaded") || registry_item[flag]) return;
  			elem.onload = elem.onreadystatechange = null;
  			onload();
  		};
  	}
docs: creates a script load listener