Microsoft's dominance of the Web is declining month-by-month, with Internet Explorer's market share falling to under 88.9 per cent.

Figures from show Microsoft's browser to have fallen five per cent since May, while the popular Firefox browser has grabbed 4.58 per cent. The battle is the Redmond software giant's to lose: Internet Explorer 6.0 still holds 81 per cent of the browser market.

OneStat's statistics are based on Web activity in 100 countries. In May, figures showed Internet Explorer with 4 per cent and Mozilla with just 2.5 per cent share.

Over five million surfers so far have downloaded the free Firefox browser, which is available for multiple platforms.

Use of Apple's homegrown Safari browser has also seen an increase, climbing to 0.91 per cent from 0.71 per cent in May.