You could try this please : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode Safe Mode : is a troubleshooting mode that temporarily turns off hardware acceleration, resets some settings, and disables add-ons (extensions and themes). If the problem goes away, that tells us one thing. If it does not, that tells us something else. If safe mode fixes the issue then try keeping hardware acceleration turned off and also disable your plugins close browser restart then try your site/s and if issue is still there then return. If issue is gone turn on things 1 by one to see if that causes the issue to come back / or not.

If above does not work : https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings Remember save passwords/bookmarks or whole profile.

Please let us know if this solved your issue or if need further assistance.

Hi   !

In case the above suggested Safe Mode doesn't do the trick :

Since last year the   'a web page is slowing down your browser'   is a new way of saying that a script is unresponsive. Would you follow the steps in this article, please, and see if that will make a difference ?

https://support.mozilla.org/en-US/kb/warning-unresponsive-script

Thanks guys for your kind support , i did every thing u told me to do but unfortunately the problem appeared again

ea_hefnawy said

Thanks guys for your kind support , i did every thing u told me to do but unfortunately the problem appeared again

Bummer   !

Would you give this a try :

Type in the address bar   about:config   (and press Enter) (promise to be careful, if asked) Type   'processHang'   in the search bar and look for the preferences : dom.ipc.processHangMonitor and : dom.ipc.reportProcessHangs

Change their values from   'true'   to   false

Does that work  ?

@Happy112 thanks lot my dear :)

ea_hefnawy said

@Happy112 thanks lot my dear :)

My pleasure   ! So glad that worked   !