My web pages are built with JSP + javascript + AJAX, so a little dynamic when loading a page (it is NOT a static HTML text page). As a common practice, when users visits my website, they can click on a hyperlink to open another webpage. When they want to go back, they can click the browser's BACK button that will bring them back to where they were. What happened to the firefox is that when its default CACHE runs out, it will display: Document Expired This document is no longer available. The requested document is not available in Firefox'x cache. ... [Try Again] The general solution is that I can go to the Options page to either increase the CACHE limit ot clean up the CACHE. But for a public user, they either do not know what to do or assume that my website has problem! Besides, all the other browsers worked fine, which include IE (8, 9, 10, and 11), Chrome, Firefox 10.0.7 for SUSE Linux, and Safari. It is the newer versions of Firefox that is failing. So my I suggest that Firefox remove its caching limitation features, instead, either using the feature implemented in the older version (of Firefox), or make it match those browsers such as IE, Chrome and Safari. Firefox was used to be user friendly. Thanks Scott