function areDigits(num) {

	var i = 0;
	var c = '';
	while (i < num.length) {
		c = num.charAt(i);
		if ((c < '0') || (c > '9')) {
			return false;
		}
		i++;
	}
	return true;
}

function checkFeedbackInfo() {

	var check	    	= true;
	var message	    	= "";
	var max_length		= 1000;
	var fullname		= document.feedback.fullname.value;
	var emailaddress	= document.feedback.emailaddress.value;
	var msg				= document.feedback.message.value;
	
	fullname = fullname.replace(/^\s+/,"");
	fullname = fullname.replace(/\s+$/,"");
	if (fullname.length == 0) {
		message += "Please fill in \"your name\" field.\n";
		check = false;
	}
	emailaddress = emailaddress.replace(/^\s+/,"");
	emailaddress = emailaddress.replace(/\s+$/,"");
	if (emailaddress.length == 0) {
		message += "Please fill in your \"email address\" field.\n";
		check = false;
	}
	if (msg.length == 0) {
		message += "Please enter your message\n";
		check = false;
	}
	else if (msg.length > max_length) {
		message += "Please use less than " + max_length + " characters in your message\n";
		check = false;
	}	
	if (! check) {
		alert(message);
	}	
	return (check);
}