FireFox
1. From the Firefox menu, select Preferences
2. Click on the Content icon
3. Make sure the Enable Java and Enable Javascript checkboxes are selected
4. Be sure Block pop-up windows is NOT checked
5. Continue on to Step 2: Enable Cookies as listed below

Safari
1. Click Safari > Preferences.
2. Click on Security at the top of the window.
3. Check the box Block pop-up windows to enable this feature. Uncheck it to disable it.

Internet Explorer
1. From the Menu, select Tools
2. Select Internet Options >> Security >> Custom level
3. Scroll down to Scripting (near the bottom of the list)
4. Select 'enable' for Active Scripting
5. Click OK
6. Continue on to Step 2: Enable Cookies as listed below

instructions sources from:
http://www.technipages.com/safari-enabledisable-pop-up-blocker.html
http://etudesproject.org/gateway/Info_BrowserTuneUp.htm