I am creating a form where users sign up to be a member of my website.

Currently the validation I'm trying to use is in Javascript, although i want it in PHP.

Could anyone please help me in creating a validation on the field named 'firstname'.

my form:
PHP Code:
<form name="registerform" id="registerform" method="post" action="signupprocess.php"
I need the validation to check if the field 'firstname' in form 'registerform' is populated, if not return an error message.

Many Thanks