I'm just guessing, but perhaps because your page is sent with headers instructing Firefox not to cache the page?

Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache

hello, your site sends the "no-store" header, so the site isn't supposed to be cached...

edit: jscher2000 was faster - sorry for the double-post :-)

thank you , but ... how did you find that it sends "no-store" ? how should I fix the problem ?

There are a couple of different add-ons you can use to view the "HTTP headers" sent by web servers when sending pages. For example, Firebug and Live HTTP Headers.

Your content management/blog platform may have a panel for managing these settings, or it could be through your web host. It's difficult to say for sure without knowing a lot of details you wouldn't want to post here.

Also, be aware that allowing browsers to cache the page may result in visitors seeing outdated content when visiting your site. You probably want to set a short interval after which the browser needs to check for updates (2 hours?) if you allow caching.

Dear madperson , you said :" your site sends the "no-store" header, so the site isn't supposed to be cached... " what should I do in order to solve the problem ?

Hi aghaye_happy, as noted in the two replies above yours, there are many ways to set the HTTP Headers your server sends, so there isn't a simple prescription for tracking down and changing it. "It depends."