function validateCF() {
	//get values of required fields
	var nameEntered = document.contactForm.name.value;
	var emailEntered = document.contactForm.email.value;
	var commentsEntered = document.contactForm.comments.value;
	
	//conditional statements
	var emptyName = (nameEntered == '');
	var emptyEmail = (emailEntered == '');
	var emptyComments = (commentsEntered == '');
	
	//create nested array pairing required fields with 'empty' condition statements
	var reqFields = new Array;
	reqFields[0] = ['NAME', emptyName];
	reqFields[1] = ['EMAIL', emptyEmail];
	reqFields[2] = ['COMMENTS', emptyComments];

	//if a required field is missing
	if (emptyName || emptyEmail || emptyComments) {

		//create warning string
		var warnString = "Please complete the following required field(s):";
		var errorCount = 0;
		
		function genErrorList(indexVal) {
			if (reqFields[indexVal][1]) {
				if (errorCount > 0) {
					warnString += ','
				}
				warnString += " " + reqFields[indexVal][0];
				errorCount += 1;
			}
		}
		
		for (i=0; i < reqFields.length; i++) {
			genErrorList(i);
		}
		
		//replace last instance of ',' with ' and'
		warnString = warnString.replace(/^(.*),(.*)$/, "$1 and$2"); 								
		
		//output alert
		alert(warnString);
								
	} else {//if all required fields are filled out
		//email validation expression
		var emailExp = "^([a-zA-Z0-9._-]+)@([a-zA-Z0-9-])+(\.[a-zA-Z0-9-]+)+$";

		//check if email is valid		
		if (!emailEntered.match(emailExp)) {
			alert ("Your email does not appear to be in a valid format. Please check and try again."); 	
		} else {//process form
			document.contactForm.submit();
		}	
	}
}


function clearCF() {
	document.contactForm.reset();
}