function IsEmpty(aTextField) {
   if ((aTextField.value.length==0) ||
   (aTextField.value==null)) {
      return true;
   }
   else { return false; }
}	

/* --- isValidEmail(strEmail) --- */
function isEmail(strEmail) {
  	return (/^[\.\w-_]+@[\.\w-_]+\.\w{2,4}$/g.test(strEmail));
}