function check_radio(itm, msg) {
var radio_choice = false;
for (counter = 0; counter < itm.length; counter++) {
if (itm[counter].checked)
  radio_choice = true;
}
if (!radio_choice)
return msg + "\n";
else
return '';
}

function check_contactform() {
	var error_message = "";
	if (document.data_form.firstname.value == "") { error_message = error_message + "* Please tell us your first name.\n";  }
	if (document.data_form.surname.value == "") { error_message = error_message + "* Please tell us your surname.\n";  }
	if (document.data_form.telephone.value == "") { error_message = error_message + "* Please tell us your telephone number\n";  }
	if (document.data_form.email.value == "") {
		error_message = error_message + "* Please tell us your email address\n";
	} else if (!(/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(document.data_form.email.value))){
		error_message = error_message + "* please enter a valid email address\n";
	}
	
	if (error_message != "") {
		alert(error_message);
		return false;
	} else {
		return true;
	}
}

function check_callbackform() {
	var error_message = "";
	if (document.data_form.name.value == "") { error_message = error_message + "* Please tell us your name.\n";  }
	if (document.data_form.telephone.value == "") { error_message = error_message + "* Please tell us your telephone number\n";  }
	if (document.data_form.email.value == "") {
		error_message = error_message + "* Please tell us your email address\n";
	} else if (!(/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(document.data_form.email.value))){
		error_message = error_message + "* please enter a valid email address\n";
	}
	
	if (error_message != "") {
		alert(error_message);
		return false;
	} else {
		return true;
	}
}