Coding Standards: Use strict comparison for JS fragment in `wp-admin/…

…admin-header.php`.

Props subrataemfluence.
Fixes #45810.

git-svn-id: https://develop.svn.wordpress.org/trunk@48083 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/admin-header.php

@@ -81,7 +81,7 @@
 $admin_body_class = preg_replace( '/[^a-z0-9_-]+/i', '-', $hook_suffix );
 ?>
 <script type="text/javascript">
-addLoadEvent = function(func){if(typeof jQuery!="undefined")jQuery(document).ready(func);else if(typeof wpOnload!='function'){wpOnload=func;}else{var oldonload=wpOnload;wpOnload=function(){oldonload();func();}}};
+addLoadEvent = function(func){if(typeof jQuery!=='undefined')jQuery(document).ready(func);else if(typeof wpOnload!=='function'){wpOnload=func;}else{var oldonload=wpOnload;wpOnload=function(){oldonload();func();}}};
 var ajaxurl = '<?php echo admin_url( 'admin-ajax.php', 'relative' ); ?>',
 	pagenow = '<?php echo $current_screen->id; ?>',
 	typenow = '<?php echo $current_screen->post_type; ?>',