Cookie script

Hi I will like to create a script or browser addon and here is how it works 1. user visits my website 2. clicks the back or exit button 3. scrip is installed on browser 4. any URL they visit that includes hop=username willl be replaced with hop=myusername an example would be [login to view URL] so my username would be after hop= Serious inquiries only, make sure you can actually complete this task before contacting me. the price is $20 for this simple job.