Therefore, we'll create CSS classes to represent these possible outcomes.
Now that we've created a working form, we need to add some j Query and Java Script to validate fields and change the CSS classes that were created earlier.
This article will explain some basics about form validation and then illustrate how to validate form fields using j Query.
There are two types of validation: client side validation and server side validation.
The only difference is that now we want to check whether the email address looks like an email address.
However, to see whether a credit card has sufficient funds requires communicating with the credit card company and that can only be done using a server side programming language.
If you are using a My SQL database, this is called My SQL Injection.
To avoid this problem, you must validate form submissions using your server.
However, if Java Script is turned on, our validation will solve any problems before the browser sees them.
We apply a little CSS to align the labels and space out the fields: The error messages should only be shown when a field has been entered incorrectly. After the form is submitted, we can reveal the error message by changing the class name with Java Script.