Affiliate ID - capture, convert, redirect

I need coding that I can place on a web page that will do as follows... 1) Have a form/field for the visitor to enter alpha-numeric data. This will be an affiliate ID that will have been provided to the visitor previously (i.e. from a print ad or business card) 2) Have a "submit" button that will initiate the following process (I should be able to change the graphic for this button). 3) Merge (concatenate) the alpha-numeric data entered by the visitor with a URL that I will provide so that it becomes a new URL (an affiliate link). The new url? should not be visible to the visitor on this web page. Example: xxxx? = data entered by visitor <[login to view URL]>? = url I provide <[login to view URL]>? = new url (affiliate link) 4) Redirect visitor to the new URL. I am open to? any changes/suggestions you may have... Thank you ## Deliverables I need notations in the code indicating? begining and ending? sections so that I know where I can customize/edit the web page. If? necessary, I may be able to provide examples of other web pages although they are probably protected by copyright.