Click in the upper menu on Edit / Options or Tools / Options. Here choose Content, Enable JavaScript and click OK.
Internet Explorer
Click in the upper menu on Tools / Internet Options.
There click at the menu Securityeither on Medium, or choose Custom Level and then activate below Scripting the point Enable Active Scripting. Confirm by clicking OK.
Google Chrome
Click on the wrench symbol on the upper right and choose Options.
There click Under the Hood, then Content settings and enable JavaScript.
Opera
Click in the upper menu on Tools / Preferences. At Advanced / Content choose Enable JavaScript and click OK.
Mozilla
Click in the upper menu on Edit / Preferences. At Advanced / Scripts & Plugins chooseNavigator. Now click on OK.