This library is a thin wrapper around giggsey/libphonenumber-for-php, itself a port of Google's libphonenumber.
In this post, you’ll learn – How to Validate Forms with PHP and it will be a server side form validation.
The form you’ll create contains a number of inputs: text fields, radio buttons, a multiple-option select list, a checkbox, and a submit button.
These inputs will be validated to ensure, for example, that the user has entered their name.
The goal is to teach you some basic HTML form elements and how their data is accessible to you in your PHP scripts.
As server side form validation is done on server, the submitted data is validated and cleaned by server and then it is used.
No one can modify those data without having access to the server. If you want, you can use get method, just change method=”get” and replace $_POST with $_GET – that’s all.
To determine whether the form has been submitted by the user, either check the request method (an example follows in the next section) or check for the presence of a specific form control (usually the submit button).
Whichever method you use, if the form has been submitted, it should be validated.
I'm not sure about 5.3.4 final, but it is written that some 5.3.4-snapshot versions also were affected.