We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Java Script Appl er msg Evc in ev handl: This .oRoot enable is not a function

  • 3 cavab
  • 122 have this problem
  • 4 views
  • Last reply by a.homemum

more options

When I try to access Firefox - I get a Java Script Application dialog box with the message. "Exc in ev handl: This o.Root enable is not a function

When I click ok it goes away and Firefox comes up. This has just started since I updated to 3.6.21 Dialog box also comes up sometimes when I go to different web pages from Firefox. But always when I try to first access Firefox.

When I try to access Firefox - I get a Java Script Application dialog box with the message. "Exc in ev handl: This o.Root enable is not a function When I click ok it goes away and Firefox comes up. This has just started since I updated to 3.6.21 Dialog box also comes up sometimes when I go to different web pages from Firefox. But always when I try to first access Firefox.

All Replies (3)

more options

I see these in your Installed Plugins listing.

  • McAfee MSC FF plugin DLL
  • SiteAdvisor

Do you have the new Site Advisor 3.4 program installed? I suspect it is causing that error message on Firefox. Disable that application or the Firefox plugins, and see McAfee support for more information.
http://community.mcafee.com/

more options

Disable "McAfee Site Advisor" extension which was just updated to 3.4.0, which probably took it out of the addons block list.

  • "Ctrl+Shift+A" > find McAfee Site Advisor and use "Disable", and then restart Firefox.
  • Do a Google Search no problem
  • It seems that if you re-enable Site Advisor again, and restart Firefox you are okay. At least you know where to look if you get the error again or Google searches slow down.
more options

I had the same problem. It really shit me off with having the message come up every time I opened FF, or opened a new window. I simply removed all McAfee programs in my control panel, and now it doesn't happen anymore. PHEWWW