document.write('<script src="js/strings.js"></script>'); 
document.write('<script src="js/querystring.js"></script>'); 


function DoQuery(textboxname) {
  var tb = document.getElementById(textboxname);
  if (escape(trim(tb.value))=='') {
    return false;
  } else {
    location.href = 'product_list.aspx?q='+StringFilter(StringFilter2(trim(tb.value)));
  }
}