Firefox extension: URL Fixer – Correct URLs entered in the address bar
The extension URL Fixer will fix common typos in URLs entered in the address bar. URL Fixer will fix errors like “google.con” or “youtube,com”. You have the option of being asked to confirm corrections before they are applied.
The extension also will correct common misspellings of .com, .net, .org, .edu, .gov, .mil, and all other mainstream TLDs, as well as the protocol (https:, https:). By right-clicking on the address bar, you can set it to auto-correct your errors, or you can have it ask you before making any corrections.
To add or remove your own corrections in URL Fixer’s options dialog, accessible via Tools » Add-ons » URL Fixer » Preferences.