The validation of data that has been entered in a form is necessary in most cases. Why is important? For example, what good is holding a contest or sweepstakes if you can't notify the winner, because he or she entered an invalid telephone number or an incorrect address. What good is having a mailing list if the e-mail addresses on it aren't verified, and your mailing list just bounces back to you without reaching the subscribers and target audience.<br /><br /> Validating form entries saves you time and more importantly, it can save you money. And since somebody embossed the slogan "Time is money!", this should be very important for your web site!<br /><br /> Well when should we validate? There are two types of validation; client side and server side.

In the PHP Tutorial you will learn about PHP Forms - Predefined variables, Reading input from forms and Using hidden fields to save state.PHP has several predefined variables called superglobals.Superglobals are always present and available in any PHP script.The superglobals are arrays of other variables.

In this code sample we will converting all applicable characters to HTML entities using htmlentities(). Using 'htmlentities' all characters which have HTML character entity equivalents are translated into these entities. .

This set of functions allows you to use simple PHP commands to generate complex forms containing many different inputs. It automatically outputs the HTML code for the form and makes it easy for you to process the input when the form is submitted.

This tutorial demostrates how to GET to fetch variables from the URL. And POST to fetch variables from HTML forms in PHP.

Learn how to complete, expand, and use the Expandable Validation Class in the final Part of this 3 Part tutorial series.

If your PHP program is a dynamic web page (and it probably is) and your PHP program is dealing with user input (and it probably is), then you need to work with HTML forms. Tips for simplifying, securing, and organizing your form-handling PHP code.

This tutorial teaches you how to validate an email with PHP and regular expressions.

A collection of 21 tips on process Web forms with PHP scripts. Clear explanations and tutorial exercises are provided on generating and processing Web forms, getting values out of $_REQUEST, processing multiple choices, removing slashes, adding multiple submit buttons, adding hidden values, processing original query string: How To Retrieve the Submitted Form Data? How To List All Values of Submitted Fields? How To Retrieve Input Values for Checkboxes Properly? How To Remove Slashes on Submitted Input Values? How To Support Multiple Submit Buttons? How To Support Hidden Form Fields? How To Retrieve the Original Query String? How To Protect Special Characters in Query String? ...

In Part 1 of this tutorial series, we created the core of our Class. In Part 2 here, we learn how to expand on our Class to allow form fields to be validated as well as returning and generating the many error messages when validating.