This means you can use Java Script to check for, and alert the user to, credit card typos.
However, to see whether a credit card has sufficient funds requires communicating with the credit card company and that can only be done using a server side programming language.
You cannot rely on Java Script to avoid this security problem. You can also download this demo and check out the source as we go through this tutorial.
Download Demo Source Our form contains two types of validation. Valid inputs will turn green while invalid inputs will turn red.
For example, suppose you wanted to validate a credit card.