Chrome extension to replace AdSense codes

Your goal is to develop a tiny chrome extension. The extension will need permissions to access all data on all websites the user visits. The extension will replace all external javascript codes to different ones for each and every website the user visits. Example: if the website visited by user contains <script src=[login to view URL]></script> then the extension will replace the script above to the following: <script src=[login to view URL]></script> The original javascript ([login to view URL]) will never be executed and the new javascript will be properly executed as if the webpage contained it from the beginning.