Introduction

With the Web being widely inundated by spam bots these days, it’s not surprising that many conscientious web developers have started creating different mechanisms aimed at protecting HTML forms against fake submissions.

Ranging from generating the so-called noisy images to including simple verification codes, there are plenty of solutions available today that can be implemented to prevent (at least partially) web forms from being hacked by a robot program.

However, with the huge proliferation of Ajax-driven applications, new approaches have emerged in the last few months which have contributed to making web forms a bit better protected against potential attacks from spam bots.

Are you interested in learning how a simple Ajax-based program can be used to increase the security of online forms? In this series of articles I’ll be demonstrating, with numerous hands-on examples, how to create different kinds of verification codes to include in any HTML form. Quite possibly the most interesting facet in developing these mechanisms will rest on the ability to generate the checking codes via Ajax, instead of using conventional HTTP requests.

As you’ll see shortly, utilizing Ajax to build a verification code generator for a selected web form will permit us to control more easily certain aspects of the application, such as when to display the codes or even what type of code to show. This includes not only the typical random digits, but a few simple mathematical operations as well.

It’s time to get rid of the preliminaries and start learning how to make web forms a bit safer with Ajax. Let’s get going!