Firefox is a web browser which allows you to view webpages on the World Wide Web. Firefox is developed by Mozilla, and is available free of charge.
Firefox 19 and later comes with its own built-in PDF viewer. To disable the built-in PDF viewer and use Adobe Reader (or another PDF viewer), go to Firefox > Preferences > Applications panel. Follow the directions listed here.
Use Firefox 24 ESR (latest build) for web applications that require it. Use Firefox 25 (latest build) for all other web browsing.
Note: Google@UH apps (gmail, gcal, gdocs) are supported on the current version of Firefox, the version just preceding it and the latest ESR version. Firefox is on a rapid-release schedule with a new version released approximately every 6 weeks. Check for the most current version of Firefox here.
Updates: If you currently have Firefox installed, click Firefox > About Firefox. Firefox will check for the latest update. Click Restart to Update. Repeat process until Firefox reports that it is up to date.