We have a php form that collects some basic information ...
This signup form is specific to one client so we want to block everyone else from signing up.
Examples of correct email addresses ...
Any address that does not use '@change-domain.co.uk' is incorrect and should throw up an error ...
"sorry - that email is not valid"
We want the check to be made before form submission - so, after the user enters their email address and tabs to the next field.