function validateFormOnSubmit() {
  var theForm = document.getElementById("contactus");
  var reason = "";
  reason += validateEmail(theForm.email);                                          
	reason += validateEmpty(theForm.firstname);
	reason += validateEmpty(theForm.phone);
	if (reason != "") {
		alert("Some fields need correction:\n" + reason);
		return false;
	}
	theForm.submit();
}

function validateEmpty(fld) {
	var error = "";
	if (fld.value.length == 0) {
		fld.style.background = 'Red'; 
		error = "The required field " + fld.name + " has not been filled in.\n"
		fld.focus();
	} 
	else {
		fld.style.background = 'White';
	}
	return error;   
}

function trim(s) {
	return s.replace(/^\s+|\s+$/, '');
} 

function validateEmail(fld) {
	var error="";
	var tfld = trim(fld.value);	// value of field with whitespace trimmed off
	var emailFilter = /^[^@]+@[^@.]+\.[^@]*\w\w$/ ;
	var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/ ;              
	if (fld.value == "") {
		fld.style.background = 'Red';
		error = "You didn't enter an email address.\n";
			fld.focus();
	} 
	else if (!emailFilter.test(tfld)) {	//test email for illegal characters
		fld.style.background = 'Yellow';
		error = "Please enter a valid email address.\n";
			fld.focus();
	} 
	else if (fld.value.match(illegalChars)) {
		fld.style.background = 'Yellow';
		error = "The email address contains illegal characters.\n";
		fld.focus();
	} 
	else {
		fld.style.background = 'White';
	}
	return error;
}