Hello Raiyad Raad, it is removed from Firefox 23 and above, you can do it only in about:config.

• javascript.enabled toggle to False

thank you

for pc's

Tools-->>Options-->> Content-->> Disable java script-->> OK-->>Save
   Finally, Refresh your browser.

MAC

Firefox-->>Preferences-->>Content-->>Disable JavaScript checkbox.

   Close the Options window to save your changes.
  refresh your browser.

Satya:

As ideato mentioned above, that option was removed starting with Firefox 23, so that won't be helpful. Ideato's method is correct/the only way to do that.

Ideato: Your answer will be marked as the solution since it's the only way to disable javascript.

It can no longer be done globally from the User Interface. There are still a few other alternatives. Depending what you need to block it may be worth considering a script blocker something such as

• No Script http://noscript.net/
• Or search for something suitable in https://addons.mozilla.org/firefox/extensions/privacy-security/

Additionally if it is a specific website that you use often and wish to for instance block just parts of the media use the permissions for that page.

• Use the pageinfo page View site information with Page Info
• Permissions Manager - Give certain websites the ability to store passwords, set cookies and more_how-do-i-manage-permissions-for-a-single-website

Satya

Maybe you are using an old version of Firefox if so it would be worth updating it

• (Don't) Install an older version of Firefox

Bring the option to disable javascript back.