The Mozilla Foundation has developed a beta patch for the Firefox browser that it claims improves the blocking of pop-up ads. The popular open-source browser already contains a pop-up blocker by default, but this doesn’t handle pop-ups launched by plug-ins such as Flash and Java. Mozilla employee Asa Dotzler wrote in his blog last week that Mozilla developers are responding to the increasing number of advertisers that are using plug-ins to launch pop-up ads.