I've got a wordpress website having a custom theme. Now after i upgrade that wordpress install to three.3.1 it appears such as the javascript is nog working properly. All pop-ups (like adding image) and processes (like falling apart boxes or opening screen options) aren't effective. Even the admin bar does not show any longer

What is the problem be? It labored fine in older wordpress website's (3.2 and fewer)

I'd an identical problem with 3.3.1, that was fixed with the addition of this to wordpress-config.php define('CONCATENATE_SCRIPTS', false);

In the event that fails, browse the Troubleshooting WordPress 3.3 Master List: http://wordpress.org/support/topic/troubleshooting-wordpress-33-master-list