Starting with build 6.1.3.0, StoreFront includes code to prevent double clicks on the Complete Order button. The instructions below will not work with build 6.1.3.0 or later and will disable the new built-in code.
The final step in the StoreFront 6 checkout process is Payment page. In this step, the credit card processor is contacted and charges are posted. It is very important that customers do not submit this page more than once. This document describes a technique to prevent StoreFront forms from being submitted more than once. It will work on any StoreFront page that uses the ValidateForm JavaScript function to validate the contents of the form fields. This includes all of the checkout pages.
The Single Click Mod is small bit of code that you add to the normal javascript page processing.
Instructions
Follow the instructions in this document to install the modification: Single Click Mod
Click here to visit the add on creators homepage