function checkContactUsForm() {
	// Hide error messages
	document.getElementById("nameError").style.display = "none";
	document.getElementById("cityError").style.display = "none";
	document.getElementById("phoneError").style.display = "none";
	document.getElementById("emailError").style.display = "none";
	
	// Get required form data
	name = document.getElementById("name").value;
	city = document.getElementById("city").value;
	phone = document.getElementById("phone").value;
	email = document.getElementById("email").value;

	if (name == "") {
		document.getElementById("nameError").style.display="inline";
		document.getElementById("name").select();
		document.getElementById("name").focus();
		return false;
	}
	else if (city == "") {
		document.getElementById("cityError").style.display="inline";
		document.getElementById("city").select();
		document.getElementById("city").focus();
		return false;
	}
	else if (phone == "") {
		document.getElementById("phoneError").style.display="inline";
		document.getElementById("phone").select();
		document.getElementById("phone").focus();
		return false;
	} 
	else if (checkPhoneNumber(phone)==false) {
		document.getElementById("phoneError").style.display="inline";
		document.getElementById("phone").select();
		document.getElementById("phone").focus();
		return false;
	}
	else if (email == "") {
		document.getElementById("emailError").style.display="inline";
		document.getElementById("email").select();
		document.getElementById("email").focus();
		return false;
	} 
	else if (! checkemail(email))	{
		document.getElementById("emailError").style.display="inline";
		document.getElementById("email").select();
		document.getElementById("email").focus();
		return false;
	}
	
	return true;
}

function checkemail(s_email){
		var filter=/^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i
		if (filter.test(s_email))
			return true;
		else{
			return false;
		}
	}
	
// Declaring required variables
var digits = "0123456789";
// non-digit characters which are allowed in phone numbers
var phoneNumberDelimiters = "()- ";
// characters which are allowed in international phone numbers
// (a leading + is OK)
var validWorldPhoneChars = phoneNumberDelimiters + "+";
// Minimum no of digits in an international phone no.
var minDigitsInIPhoneNumber = 7;
var phonenumber = document.forms[n].phone.value;

function isInteger(s)
	{   var i;
			for (i = 0; i < s.length; i++)
			{
					// Check that current character is number.
					var c = s.charAt(i);
					if (((c < "0") || (c > "9"))) return false;
			}
			// All characters are numbers.
			return true;
	}

function stripCharsInBag(s, bag)
	{   var i;
			var returnString = "";
			// Search through string's characters one by one.
			// If character is not in bag, append to returnString.
			for (i = 0; i < s.length; i++)
			{
					// Check that current character isn't whitespace.
					var c = s.charAt(i);
					if (bag.indexOf(c) == -1) returnString += c;
			}
			return returnString;
	}

function checkPhoneNumber(strPhone) {
	s=stripCharsInBag(strPhone,validWorldPhoneChars);
	return (isInteger(s) && s.length >= minDigitsInIPhoneNumber);
	}