PHP Form & component validation Tutorials

PHP forms and validation roadmap: Start with form basics and explicit POST/GET handling, then learn sticky inputs, checkboxes, radio buttons, select boxes and server-side validation. Validate external input for its intended purpose and escape values when rendering them into HTML.

Two Ways to Validate Form Input in PHP

PHP provides different ways to check and validate user input. Use PHP Filters when you need to validate or sanitize values such as email addresses, URLs, integers, IP addresses, and booleans. Use ctype functions when you need to check the characters inside a string, such as whether it contains only letters, digits, spaces, or alphanumeric characters.

PHP Filters
Validate and sanitize external values with PHP's Filter extension, including email, URL, IP, integer, float, boolean and regular-expression checks. ctype Character Validation
Check whether an entire string contains digits, letters, alphanumeric characters, whitespace, punctuation, hexadecimal characters and other character classes.

Forms are mainly used to collect user entered data to the system. We enter our login data or use one signup form to enter data as a user to a database table or to a form processing script. There are different components like text box, radio buttons, checkbox, combo box or drop down list boxes for users to enter data to a system. You can read more details on web form and its components in our HTML section.
HTML form input and data receiving page

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HTML FORM basics with input fields submit button action page and target attributes

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To handle various display and design issues we have to use front end tool like HTML or JavaScript. Our server side script PHP is used to handle the data as entered by users. We also need PHP to validate the data and post back the error messages if validation fails.

We will discuss some basic issues relating to handling of form components and some sample codes here.

Variables and sending data

Creating variables in PHP
Sending data across pages using POST and GET methods.

Check Box

Checkbox How to use and handle checkbox data.
Checkbox data How to handle the post back data for a check box if validation fails?
Checkbox & database Retrieving and storing data of checkbox

Validation and Checks of user entered data

How to retain form data Retaining the data in the form if it fails to submit
Date validation Validating user entered date value.
Sample codes to check data entered through Web forms
Email Validation Checking format of user entered email address
Email Validation using Ajax Using Ajax to validate email address
Checking for number only Returns falls if data is not a number
is_int Checks if data is an integer or not
intval Getting integer part from data.
ctype character validation Check complete strings for letters, digits, alphanumeric content, whitespace, punctuation and other character classes.