function addClass(element,value) {
	if (!element.className) {
		element.className = value;
	} else {
		newClassName = element.className;
		newClassName+= " ";
		newClassName+= value;
		element.className = newClassName;
	}
}

function validate_required(field,thisform)
{
with (field)
{
  if (value==null||value=="")
  {
	addClass(thisform,'error');
	return false;
  }
  else
  {
  return true;
  }
}
}