Look at this recent Mozilla thread, asking the same question: http://groups.google.com/group/mozilla.dev.platform/browse_thread/thread/8724106c2dce0be2# http:/

Look at this recent Mozilla thread, asking the same question: http://groups.google.com/group/mozilla.dev.platform/browse_thread/thread/8724106c2dce0be2# http://groups.google.com/group/mozilla.dev.platform/browse_t... It offers reasons why it's a bad idea, and an alternative (in HTML5 instead of HTTP).