Credit Card Validation with JavaScript and Regular Expressions
Continuing from the last post, for the javascript I checked the credit card number of form submittal, (along with a lot other things, like required fields, correct phone numbers, etc… ) and if it isn’t correct, throw an alert and prevent the form from submitting (Ignore the PHP tags, haven’t gotten around to adding a generic code highlighting plug yet…).
<?php
var ccType = document.getElementById(‘credit_card’).value;
switch(ccType) {
case ‘AMEX’:
var goodCC = /^3[47]{1}[0-9]{13}$/;
break;
case ‘Visa’:
var goodCC = /^4[0-9]{15}$/;
break;
case ‘Mastercard’:
var goodCC = /^5[1-5]{1}[0-9]{14}$/;
break;
case ‘Discover’:
var goodCC = /^6011[0-9]{12}$/;
break;
default:
var goodCC = /^[0-9]{15,16}$/;
}
if(!goodCC.test(ccNum)) {
problem += “Please enter in a valid credit card number (only use numbers)n”;
}
}
if (problem != ‘’) {
alert(problem);
//code to stop the form from submitting
}
?>