Microsoft's Office 2010 is moving to the web, but the browser-based apps apparently might not work in Opera or Google's Chrome.
With the next release of its Office suite, Microsoft will be offering free web-based versions of Word, Excel and PowerPoint.
A post on the Office Web Apps blog said the online productivity suite will officially support Internet Explorer 7 and 8, Firefox 3.5 and Safari 4.
That leaves out Opera and Chrome, which win about two per cent market share each, according to Net Applications.
The post also leaves out IE6. While that browser is seven years old, it is still used by a quarter people online - despite efforts to kill it off.
"If you prefer to use another browser you should still give the Web Apps a try," the blog post said. "While we cannot officially support all browsers, customers will not be blocked from using them. It is a goal of the Web Apps to have broad compatibility and reach."
Despite including Mozilla's Firefox in the official browser lineup, the blog post still took a dig at its biggest rival.
"While we strive to make the experience consistent across each browser we support, sometimes this isn't possible. A browser may not offer the same level of extensibility for certain scenarios," it said.
"One example of this is copying text by pressing the copy' button on the ribbon. In Internet Explorer this will work (after a prompt), but Firefox doesn't support copying to the clipboard through mouse actions, so you'll see a dialog from the Office Web Apps," it noted.
Silverlight
Microsoft also used the opportunity to push its Adobe Flash rival, Silverlight. While the Office Web Apps will work without installing Silverlight, users will be prompted to download it as it improves the "viewing experience."
In Word, Microsoft promised pairing Silverlight with the Office apps will boost speeds, improve font appearance and settings, and offer better accuracy using the Find tool.
In PowerPoint, Silverlight will smooth out animations and allow scaling with the browser window.
"If you'd prefer not to install Silverlight the Office Web Apps will still work well in the browser you choose to use - allowing you to work anywhere, no matter what machine setup you happen to find," Microsoft noted in the blog post.
Microsoft released Silverlight 3 last month.
