Relying on HTML 'required' for simple form validation

Question

My question is simple, I\'m writing a simple login/registration form for my website using HTML, PHP and jQuery.

Is it neccesary to write the form validation in PHP also

Answer 1

You should never rely on the frontend validation. Nor Javascript or HTML. Users can open your reg form, use firebug or some other tool, inspect the text box and DELETE the required attribute. Also can send to your backend POSTed variable, even without opening your frontend