If you’ve just started using Firefox it’s likely you’re still poking around its options and customizing it as per your preference. In the process you might have noticed that unlike Chrome or Internet Explorer, Firefox allows you to tweak just about anything from about:config.While the option opens a whole new world of customization for those who know what to do, the average user might be fairly clueless making it very difficult to tweak something simple like the default search engine in the URL bar. If like many people, you use only the URL bar to both search the web and enter web addresses, you might want to set the search engine as per your own preference and Choose Search Engine is a Firefox extension that let’s you do that easily.
Once installed, go to the extension’s options and choose one of the listed search engines or enter a custom URL. The extension requires no restart and the changes are implemented immediately after you click OK. The extension modifies the keyword.URL preference in about:config and replaces it with whichever search engine you choose or the URL you enter.
Install Choose Search Engine Extension For Firefox