function validate() {
	valid = true; 
	var emailChecked = false;
	var phoneChecked = false;
	var commentChecked = false;
	

	if (document.contact_form.email.value != "") {
	var email = document.contact_form.email.value;
		if ((email.indexOf(".") > 2) && (email.indexOf("@") > 0)) {
			valid = true;
		}
		else {
			alert('Please enter a valid e-mail address');
			emailChecked = true;
			valid = false;
			
		}
	}
	
	if (document.contact_form.phone.value != "") {
	var phone = document.contact_form.phone.value;
	phoneNumber = new RegExp(/\d{3}\-\d{3}\-\d{4}/);
		if (phoneNumber.test(phone) && emailChecked == false) {
			valid = true;
		}
		else if (!phoneNumber.test(phone)){
			alert("Phone number must be in XXX-XXX-XXXX format.");
			phoneChecked = true;
			valid = false;
		}
	}
	
		if (document.contact_form.message.value != "") {
		var message = document.contact_form.message.value;
		if ((message.length < 400) && phoneChecked == false && emailChecked == false) {
		valid = true;
		}	
		else if ((message.length > 400) && phoneChecked == false && emailChecked == false)  {
		alert('Please limit your message to 400 characters.');
		commentChecked = true;
		valid = false;
		} 	
	}

		if ((document.contact_form.name.value == "") || (document.contact_form.email.value == "") || (document.contact_form.phone.value == "") || (document.contact_form.message.value == "")){
	valid = false; 	
	}

	if (valid == false && emailChecked == false && phoneChecked == false && commentChecked == false) {
		alert('Please ensure all mandatory fields have been filled out before proceeding.');
	}	
	return valid;
}