Data Validation

Some quick references here to data validation resources.  Many or most of these resources will refer to the Validate plugin for jQuery.

Server Side

http://phpmaster.com/form-validation-with-php/

Client Side

Much of client side data validation will center around jQuery.

Tutorials:

• jQuery Tutorials
• Tutorials on jQuery.com
• Form Validation using jQuery (Includes coding a method to validate a drop-down list.)

Custom Rules

•  jQuery Validate Plugin: Creating Custom Rules 
• Random Acts of Coding: How to write custom validation rules Includes list of built-in validation rules.
• Unique Username Validation Rule

Conditional Validation

• Conditional validation of a group.
• A group of controls appears or disappears based on the state of another control.
• Also formats/masks the phone number field

Notes

To test if jQuery library is loaded, place the following in the HEAD of your document:

<script type="text/javascript">// <![CDATA[
  $().ready(function() {
    alert("HELLO");
  });
// ]]></script>