Microsoft’s Internet Explorer has been the top browser in the world since the company bought Netscape nearly 15 years ago. Mozilla’s Firefox gained modest share over the last several years. But, it is Google’s Chrome that has finally caught up to everyone else.

According to StatCounter, Google’s Chrome 15 has become the most popular web browser version worldwide for the first time on a weekly basis. The firm’s research reports, “The last week in November, Chrome 15 took 23.6 percent of the worldwide market compared to Microsoft’s Internet Explorer 8 at 23.5 percent. If one aggregates all versions then IE still leads the global market with Chrome in second position, having overtaken FireFox in November.”

After November, Microsoft’s Internet Explorer (IE) resumed its usage share slide in December, dropping to a new low and setting the stage for a fall below 50 percent as early as March. Google’s Chrome benefitted most from IE’s decline, growing its share by nine-tenths of a percentage point to a record high of 19.1 percent. Chrome should crack the 20 percent mark either this month or February.

The widespread use of Google Android on wireless devices and tablets has most likely helped improve Chrome’s market share particularly in the world of smartphones.

StatCounter said that Google Chrome’s market share grew 84 percent in 2011 – saying that it is now used as the primary web browser on 27 percent of computers worldwide. Internet Explorer is still in the lead, commanding 39 percent of global web browsers market share. However, if the current trends continue, Chrome is set to pass Internet Explorer sometime in 2012.

Ellis Hamburger, writer for Business Insider, said just because one place is reporting numbers doesn’t make it true and said there is no way to determine if Chrome is going to surpass IE.

“StatCounter’s data should not be considered fact. Net Applications has Chrome at only 22 percent (which is smaller than FireFox, but still growing fastest amongst competitors) and Internet Explorer at 52 percent,” said Hamburger, showing that IE is still in double-digit percents above the competitor.

Net Applications calculates browser usage share with data obtained from more than 160 million unique visitors who browse 40,000 Web sites that the company monitors for clients. Firefox will lose its second-place spoke to Chrome in March if the two browsers keep to their current Net Applications’ trend lines – meanwhile, StatCounter is reporting that Chrome has already overtaken FireFox.