function validate_enquiry_form ( )
{
		valid = true;
    errormessage = '';
		
		if ( document.enquiryform.forename.value == "" ){
  			errormessage += '- your forename'+"\n";	
				valid = false;
    }

		if ( document.enquiryform.surname.value == "" ){
  			errormessage += '- your surname'+"\n";	
				valid = false;
    }
		
		if ( ( document.enquiryform.emailaddress.value == "" ) 
				|| (is_email_invalid(document.enquiryform.emailaddress.value)) ){
  			errormessage += '- a valid email address'+"\n";	
				valid = false;
    }
		
		if ( document.enquiryform.enquiry.value == "" ){
  			errormessage += '- an enquiry message'+"\n";	
				valid = false;
    }		

		if (!valid){
			alert ( "Please double check your details"+"\n"
							+"You must supply:"+"\n"+errormessage );		
		}
    return valid;
}

function is_email_invalid(x)
{
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(x)){  return false; }
	else{ 								return true;}
}