AJAX and PHP

Chapter 4
Always validate user input on the server.
The application you are about to build validates a registration form, as shown in Figure 4.2, using
both AJAX validation (client side) and typical server-side validation:
• AJAX-style—when each form field loses focus (onblur). The field's value is sent to
the server, which validates the data and returns a result (0 for failure, 1 for success).
If validation fails, an error message will unobtrusively show up and notify the user
about the failed validation as shown in Figure 4.3.
• PHP-style—when the entire form is submitted. This is the usual validation you
would do on the server, by checking user input against certain rules. If no errors are
found and the input data is valid, the browser is redirected to a success page as
shown in Figure 4.4. If validation fails, however, the user is sent back to the form
page with the invalid fields highlighted as shown in Figure 4.3.
Both AJAX validation and PHP validation check the entered data against these rules:
• Username must not already exist in the database
• Name field cannot be empty
• A gender must be selected
• Month of Birth must be selected
• Birthday must be a valid date (between 1-31)
• Year of birth must be a valid year (between 1900-2000)
• The date must exist taking into consideration the number of days for each month
• Email address must be written in a valid email format, such as filip@yahoo.co.uk or
cristian@subdomain.domain.com
• Phone number must be written in standard US form: xxx-xxx-xxxx
• "I've read the Terms of Use" must be checked
Watch the application in action in the following screenshots:
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