Chrome Extension converted to FireFox XPI extension

I need a chrome extension converted to firefox XPI extension, the chrome extension captures the onbefore request of a xmlhttprequest and modifies the url before the request is made. The chrome extension works fine and took 30mins to create, We need someone to create a basic firefox extension that does the same as a chrome extension. I have attached the chrome extension source, once you have installed chrome extension visit [login to view URL] to test the onbefore xmlhttprequest, you will see a test button. We just need this done in firefox XPI extension. The onbefore request links are inside \js\[login to view URL] of the chrome extension.