Firefox's share of the web browser market slipped a bit in July, while Internet Explorer gained by an equal amount, a website analysis firm said Friday.

Market share for the Mozilla Foundation's open-source browser dipped to 8.07 percent in July from a high of 8.71 percent in June, according to NetApplications, which gathered the data from the 40,000 websites it monitors.

Microsoft Corp.'s Internet Explorer, on the other hand, increased its market share to 87.2 percent from 86.56 percent, the Aliso Viejo, Calif.-based, company, said. The Mac browser Safari showed modest growth to 2.13 percent, while most other browsers experienced little change.

“Microsoft’s Internet Explorer actually gained ground at the expense of FireFox," Dan Shapero, chief operating officer for NetApplications, said in a statement.

While at 8.07 percent, Firefox was reaching mass appeal; August was expected to be a "telling month," Shapero said.

Earlier this month, the non-profit Mozilla Foundation launched a for-profit subsidiary to take over the development and marketing of Firefox and the group's Thunderbird email client. The Mozilla Corp. was formed to eliminate legal and tax issues that would arise, if the foundation tried to make money from its desktop products, officials said.

Market share for other browsers in July were 1.5 percent for Netscape, 0.49 percent for Opera, 0.52 percent for Mozilla and 0.09 percent for others, according to NetApplications.