Firefox incompatibility bug

Avg Bid (USD)
Project Budget (USD)
$20 - $25

Project Description:
If you look at:

enter a number or use the arrow button to select ticket quantity.
either textbox, it's ok.
and then add the tickets to your cart.

In Internet Explorer this works fine.
However in FireFox this does not.

your task is to let me know what the issue is.

Here is a zip file of the entire app:

Skills required:
.NET, ASP, C# Programming, Engineering, Javascript, MySQL, PHP, Project Management, Software Architecture, Software Testing, Web Hosting, Website Management, Website Testing
Hire uswebpro
Project posted by:
uswebpro Czech Republic
Public Clarification Board
Bids are hidden by the project creator. Log in as the employer to view bids or to bid on this project.
You will not be able to bid on this project if you are not qualified in one of the job categories. To see your qualifications click here.