function validate_required(field, alerttxt)
		{
			with (field)
			{
				if (value==null || value=="")
				{
					alert(alerttxt);
					field.focus();
					return false;
				}
				return true;
			}
		}
		
		function validate_matching(field1, field2, alerttxt)
		{
			if (field1.value != field2.value)
			{
				alert(alerttxt);
				field1.focus();
				return false;
			}
			return true;
		}
		
		function validate_email(field, alerttxt)
		{
			with (field)
			{
				apos = value.indexOf("@");
				dotpos = value.lastIndexOf(".");
				if (apos < 1 || dotpos-apos < 2) 
				{
					alert(alerttxt);
					field.focus();
					return false;
				}
				return true;
			}
		}
		
		function validate_form(form)
		{
		
			with (form)
			{
				if (validate_required(name,"Please enter your name.") == false) { return false; }
				if (validate_required(email1,"Please enter an e-mail address.") == false) { return false; }
				if (validate_required(email2,"Please enter an e-mail address.") == false) { return false; }
				if (validate_matching(email1, email2, "Please check that you have typed your e-mail address correctly in both fields.") == false) { return false; }
				if (validate_email(email1, "Please enter a valid e-mail address.") == false) { return false; }
				if (validate_required(message,"Please enter a message.") == false) { return false; }
				
				return true;
			}
		}