Firefox

Click in the upper menu on Tools / Options. Here choose Enable JavaScript and refresh page with F5.

Internet Explorer

Click in the upper menu on Tools / Internet Options.There click at the menu Security either on Medium, or choose Custom Level and then activate below Scripting the point Enable Active Scripting. Refresh page with F5.

Mozilla

Click in the upper menu on Edit / Preferences. At Advanced / Scripts & Plugins chooseNavigator. Now refresh page with F5.

Opera

Click in the upper menu on Tools / Preferences. At Multimedia choose Enable JavaScript and refresh page with F5.