function check_required(field, fieldtext)
{
	if(field.value == null || field.value == "")
	{
		alert('Please enter your ' + fieldtext + '.');
		field.focus();
		return false;
	}
	else
	{
		return true;
	}
}

function check_input(form)
{
	with(form)
	{
		if(!check_required(name, 'name')) return false;
		if(!check_required(surname, 'surname')) return false;
		if(!check_required(address, 'mailing address')) return false;
		if(!check_required(city, 'city')) return false;
		if(!check_required(state, 'state')) return false;
		if(!check_required(code, 'ZIP code')) return false;
		if(!check_required(phone, 'phone number')) return false;
		if(!check_required(email, 'email address')) return false;
		
		// validate email
		with(email)
		{
			var atpos=value.indexOf("@");
			var dotpos=value.lastIndexOf(".");
			if (atpos<1||dotpos-atpos<2)
			{
				alert('Please enter a valid email address.');
				focus();
				return false;
			}
		}
		
		// validate date of birth
		if(dob_y.selectedIndex == 0 || dob_m.selectedIndex == 0 || dob_d.selectedIndex == 0)
		{
			alert('Please enter your birthday.');
			dob_d.focus();
			return false;
		}
		
		if(isNaN(code.value))
		{
			alert('Please enter a numeric ZIP code.');
			code.focus();
			return false;
		}
		
		if(isNaN(phone.value))
		{
			alert('Please enter a numeric phone number.');
			phone.focus();
			return false;
		}
		
		if(emergency_phone.value != '' && isNaN(emergency_phone.value))
		{
			alert('Please enter a numeric emergency phone number.');
			emergency_phone.focus();
			return false;
		}
		
		if(mobile.value != '' && isNaN(mobile.value))
		{
			alert('Please enter a numeric mobile phone number.');
			mobile.focus();
			return false;
		}
		
		
		if(!agree.checked)
		{
			alert('Please agree to all Terms and Conditions.');
			return false;
		}
	}
	return true;
}

function check_values(form)
{
	with(form)
	{
		//if(!check_required(refId, 'reference Id')) return false;
		//if(!check_required(name, 'subscription name')) return false;
		//if(!check_required(length, 'subscription length')) return false;
		//if(!check_required(unit, 'subscription unit')) return false;
		//if(!check_required(startDate, 'start date')) return false;
		//if(!check_required(totalOccurrences, 'total occurrences')) return false;
		//if(!check_required(amount, 'amount')) return false;
		if(!check_required(cardNumber, 'card number')) return false; 
		if(!check_required(expirationDate, 'expiration date')) return false;
		if(!check_required(firstName, 'first name')) return false;	
		if(!check_required(lastName, 'last name')) return false;	
}
	return true;
}

function update_values(form)
{
	with(form)
	{
		if(!check_required(subscriptionId, 'subscription Id')) return false;
		if(!check_required(cardNumber, 'card number')) return false; 
		if(!check_required(expirationDate, 'expiration date')) return false;
		if(!check_required(firstName, 'first name')) return false;	
		if(!check_required(lastName, 'last name')) return false;	
}
	return true;
}

function delete_values(form)
{
	with(form)
	{
		if(!check_required(subscriptionId, 'subscription Id')) return false;
	}
	return true;
}