The U.S. maker of the popular Firefox browser says it will go ahead with plans to block the most common forms of Internet tracking. Mozilla, in Mountain View, Calif., said the decision would allow hundreds of millions of Firefox users to control who watches their web browsing habits and destinations, The Washington Post reported Wednesday. The announcement comes amid intense opposition from advertising groups, who maintain tracking is the only way to provide targeted, lucrative ads that in turn fund many popular Internet services. Mozilla officials said they are building sophisticated tools to limit the placement of \"cookies\" in users\' browsers, small pieces of code that can track a user\'s Internet travels over extended periods of time. Firefox would still allow tracking if users gave a website explicit permission to use cookies. \"We\'re trying to change the dynamic so that trackers behave better,\" Brendan Eich, chief technology officer for Mozilla, told the Post.