The NoScript Firefox extension provides extra protection for Firefox. This free, open source extension allows plugins to be executed only by trusted web sites of your choice and provides the most powerful anti cross-site scripting protection available in a browser.
To Install in Thunderbird:
1. Right-click the link below and choose "Save Link As..." to download and save the file to your hard disk.
2. In Mozilla Thunderbird, open Add-ons from the Tools menu.
3. Click the Install button, and locate/select the file you downloaded and click "OK".