function ValidateForm(){

	for(var i=0;i<frmContactUs.length;i++){

		if(frmContactUs.elements[i].name=="txtFirstName" || frmContactUs.elements[i].name=="txtLastName" || frmContactUs.elements[i].name=="txtComments" || frmContactUs.elements[i].name=="txtEmailAddress"){

			if(frmContactUs.elements[i].value==""){
				alert("You have not filled in all mandatory fields.");
				frmContactUs.elements[i].focus();
				return false;
			}
		}
		

			//check email
			if(frmContactUs.elements[i].name=="txtEmailAddress"){
					var email = document.frmContactUs.txtEmailAddress.value;
					if(email == "" || email.indexOf('@',0)== -1 || email.indexOf('.',0)== -1){
						alert("Email address is not valid");
						document.frmContactUs.txtEmailAddress.focus();
						return false;
			}
			

		}

	}


	//ok
	return true;
	
}