The purchase of Quick Office by Google in June last year is finally showing results, in ChromeOS at least; with the newest flag to be enabled allowing users to edit Microsoft Word and Excel files in the browser.
The option is available via the chrome://flags tab and finding the ‘Enable document editing’ flag and enabling it. This flag is only available in the Developer Channel in ChromeOS. While Developer mode can give some interesting results and tends to be on occasion a little unstable it can offer some pretty good perks.
If you find any bugs, they should be reported via this custom link.
Enable the flag and try it out for yourself.