If you don’t want your users to send out incoming missile alerts accidentally then form validation is critical.
Let’s create a form that we’ll work with: would give us the value for the user’s first name they provided.
When an element is valid: If you want to take control over the look and feel of native error messages, or if you want to deal with browsers that do not support HTML's built-in form validation, you must use Java Script.More and more browsers now support the constraint validation API, and it's becoming reliable.You can use it simply like this: function that removes special characters for use in a SQL statement.I hope this article provides a good starting point as you begin to think about incorporating form validation with PHP.All of those functions and a lot more are easy to accomplish with PHP.
We will focus on doing something with the data in future topics, but for now, we just want to perform some simple validations.
Rule #1 in web development is never trust the user.
Now that is not to say that every user your project encounters is looking to commit a malicious act.
If correct, the application allows the data to be submitted to the server and (usually) saved in a database; if not, it gives you an error message explaining what corrections need to be made.
Form validation can be implemented in a number of different ways.
This API consists of a set of methods and properties available on each form element.