diff --git a/wp-admin/admin-header.php b/wp-admin/admin-header.php
index 3942b7cf98..5c0000dd76 100644
--- a/wp-admin/admin-header.php
+++ b/wp-admin/admin-header.php
@@ -20,8 +20,7 @@ get_admin_page_title();
 <?php wp_admin_css(); ?>
 <script type="text/javascript">
 //<![CDATA[
-function addLoadEvent(func) {if ( typeof wpOnload!='function'){wpOnload=func;}else{ var oldonload=wpOnload;wpOnload=function(){oldonload();func();}}}
-//]]>
+addLoadEvent=(function(){var e=[],t,s,n,i,o,d=document,w=window,r='readyState',c='onreadystatechange',x=function(){n=1;clearInterval(t);while(i=e.shift())i();if(s)s[c]=''};return function(f){if(n)return f();if(!e[0]){d.addEventListener&&d.addEventListener("DOMContentLoaded",x,false);/*@cc_on@*//*@if(@_win32)d.write("<script id=__ie_onload defer src=//0><\/scr"+"ipt>");s=d.getElementById("__ie_onload");s[c]=function(){s[r]=="complete"&&x()};/*@end@*/if(/WebKit/i.test(navigator.userAgent))t=setInterval(function(){/loaded|complete/.test(d[r])&&x()},10);o=w.onload;w.onload=function(){x();o&&o()}}e.push(f)}})();//]]>
 </script>
 <?php if ( ($parent_file != 'link-manager.php') && ($parent_file != 'options-general.php') ) : ?>
 <style type="text/css">* html { overflow-x: hidden; }</style>