function check_form(f)
{
  err = new Error();
  if (isempty(f.title)) err.add('Title is mandatory. Please re-enter.');
  if (isempty(f.first_name)) err.add('First name is mandatory. Please re-enter.');
  if (isempty(f.last_name)) err.add('Last name is mandatory. Please re-enter.');
  if (isempty(f.company)) err.add('Company is mandatory. Please re-enter.');
  if (isempty(f.address_line_1)) err.add('Address line 1 is mandatory. Please re-enter.');
  if (isempty(f.town)) err.add('Town is mandatory. Please re-enter.');
  if (isempty(f.postcode)) err.add('Postcode is mandatory. Please re-enter.');
  
  if (f.newsletter.checked)
  {
    if (isempty(f.email))
	  err.add('In order to be added to the PB Corporate Events mailing list please fill in your email.');
    else
	{
		emailpat = /^([a-zA-Z0-9])+([\.a-zA-Z0-9_-])*@([a-zA-Z0-9_-])+(\.[a-zA-Z0-9_-]+)+$/;
		if (!emailpat.test(f.email.value)) 
	    {
			err.add('Your email is not recognised as a valid format. Please re-enter.');
		}
	}
  }

if (err.isset()){
    err.show();
    return false;
  }
  return true;
}