Help with Google Chrome Extension

I'm trying to get movie listings using Rotten Tomatoes' API. When I run my code as a regular webpage, it works. But when I load it as an extension along with the manifest file, it doesn't work. The text box and the submit button show up, but when I enter the movie name, nothing happens. I have included the code as attachment. (Note: I have purposely excluded the API key for obvious reasons, but if you need the API key, I can provide it in a personal message.)