function validate_required(field){
	with (field){
		if (value==null||value=="")
  			{document.getElementById('error').innerHTML ='Please fill in fields before submitting';return false;}
	else {return true}
	}
}

function validate_check(field){
	with (field){
		if (checked==false)
  			{document.getElementById('error').innerHTML ='Please accept terms and conditions and certify that you are over 18';return false;}
	else {return true}
	}
}

function validate_form(thisform){
	with (thisform){
		if (validate_required(firstname)==false){
			firstname.focus();return false;
		}
		if (validate_required(surname)==false){
			surname.focus();return false;
		}
		if (validate_required(email)==false){
			email.focus();return false;
		}
		if (validate_check(terms)==false){
			terms.focus();return false;
		}	
		if (validate_check(cert)==false){
			cert.focus();return false;
		}	
	}
}