Hi there! I am new to this site so don't yet have any ratings, but I know I can help you out with your problem. I submitted a lower bid to make sure that you can get the job done for only a small amount of money. I've been working with HTML, CSS, and Javascript for almost 5 years now, so I should be able to add in the script very quickly.
Please let me know if you have any questions for me — I'm happy to talk over the phone, chat, or email!
Looking forward to working with you.