CloudOn has just expanded from mobile-only to web.

The two-year-old productivity service, which allows you to open, edit and use Microsoft Office documents on Android and iOS mobile devices, launched a web version of its document editor on Tuesday. All you have to do is install a browser plugin for either Chrome or Safari.

CloudOn's new availability in the browser allows users to continue productivity work while on either Mac and Windows computers - rather than be limited to tablets and smartphones. There is one catch, though: some functionality costs money.

CloudOn has simultaneously announced a CloudOn Pro service. It's a paid service, where subscribers pay a yearly or monthly fee and get access to certain Microsoft Office features like Word's change tracking.

CloudOn's web app is free, but going pro will cost $30 a year. That's a special introductory price, too. CloudOn Pro will cost $80 a year starting in 2014. Watch the video from CloudOn below for more information.