Several years ago the Firefox Web browser brought serious competition back to Web browsers, a market then overwhelmingly dominated by Microsoft Corp.'s Internet Explorer. Now Google Inc. is shaking up the browser market again.

Google's Chrome Web browser reached 7.24% of the world-wide browser market in June and is the fastest-growing program for surfing the Web, according to data from NetApplications.com, which tracks Web usage. Google says Chrome had more than 70 million active users in May, up from 30 million in June 2009.

Google's new No. 3 position in browsers has added to the company's clout in defining technical standards that shape Web sites and funneling Web surfers to its Internet search engine.

'The browser matters because of its ability to drive access to other assets,' says Sheri McLeish, an analyst at Forrester Research.

Google's determination to gain a foothold in the market shows how browsers are again becoming an important battleground as more software development shifts to the Web from applications anchored to personal-computer operating systems like Windows and Macintosh.

Google is trying to nudge the shift even further with a new operating system called Chrome OS that is derived from its browser and designed to run only Web-based software. Chrome OS laptop computers are expected to come out from Google hardware partners this fall. 'When the Web gets better, Google tends to benefit,' says Sundar Pichai, vice president of product development at Google.

The browser war of the late 1990s between Microsoft and Netscape Communications Corp. was the first great competitive struggle of the Internet era, ending in a bruising series of antitrust court battles for Microsoft and the fading of Netscape into oblivion. Microsoft's Internet Explorer emerged from that battle with a share of the browser market that once exceeded 90% until Firefox came along.

Firefox is an open-source browser built with contributions from volunteerprogrammers overseen by the Mozilla Foundation, a nonprofit group descended from an organization created by Netscape in the late '90s. It found a receptive audience, partly because of the proliferation of malicious code that exploited security vulnerabilities in Internet Explorer.

Many consumers viewed Firefox as a more innovative and secure alternative, helping the software take the No. 2 position. Usage of the browser peaked at 24.7% in November, but had slid to 23.8% by June, according to NetApplications.

Nick Wingfield / Amir Efrati

• competition [,kɔmpi´tiʃən] n.比赛；竞争 (初中英语单词)
• program [´prəugræm] n.说明v.为...安排节目 (初中英语单词)
• ability [ə´biliti] n.(办事)能力；才干 (初中英语单词)
• system [´sistəm] n.系统，体系，制度 (初中英语单词)
• series [´siəri:z] n.连续；系列；丛书 (初中英语单词)
• foundation [faun´deiʃən] n.建立；基金；地基 (初中英语单词)
• audience [´ɔ:diəns] n.听众；观众；接见 (初中英语单词)
• partly [´pɑ:tli] ad.部分地；不完全地 (初中英语单词)
• security [si´kjuəriti] n.安全；证券；抵押品 (初中英语单词)
• explorer [ik´splɔ:rə] n.勘探者；探险家 (高中英语单词)
• technical [´teknikəl] a.技术的；专门性的 (高中英语单词)
• access [´ækses] n.接近；通路；进入 (高中英语单词)
• determination [di,tə:mi´neiʃən] n.决心；决定 (高中英语单词)
• ending [´endiŋ] n.结尾，结局 (高中英语单词)
• volunteer [,vɔlən´tiə] n.志愿者 v.自愿做 (高中英语单词)
• trying [´traiiŋ] a.难堪的；费劲的 (英语四级单词)
• hardware [´hɑ:dweə] n.五金器皿 (英语四级单词)
• competitive [kəm´petitiv] a.竞争的，比赛的 (英语四级单词)
• alternative [ɔ:l´tə:nətiv] a.二中选一的 n.选择 (英语四级单词)
• foothold [´futhəuld] n.立足点；据点 (英语六级单词)
• oblivion [ə´bliviən] n.(被)忘却；漠视 (英语六级单词)
• malicious [mə´liʃəs] a.恶意的；预谋的 (英语六级单词)