var emailExp = /^[\w\-\.\+]+\@[a-zA-Z0-9\.\-]+\.[a-zA-z0-9]{2,4}$/;
var numericExp = /^[0-9]+$/;

function validateSignUp() {
	var nameFirst = document.getElementById('nameFirst');
	var nameLast = document.getElementById('nameLast');
	var email = document.getElementById('email');
	var zip = document.getElementById('zip');

	if(nameFirst.value.length <= 0) {
		alert("You must enter your first name in order to submit this form.");
		return false;
		signUp.nameFirst.focus();
	}
	if(nameLast.value.length <= 0) {
		alert("You must enter your last name in order to submit this form.");
		return false;
		signUp.nameLast.focus();
	}
	if(!document.getElementById('email').value.match(emailExp) || document.getElementById('email').value.length <= 0) {
		alert("There is a problem with your e-mail address. Please check it and resubmit.");
		return false;
		signUp.email.focus();
	}
	if(!document.getElementById('zip').value.match(numericExp) || document.getElementById('zip').value.length != 5) {
		alert("There is a problem with your zip code. Please check it and resubmit.");
		return false;
		signUp.zip.focus();
	}
	return true;
}