How to set up custom search in destoon_PHP tutorial

function loseSpace($pcon){
$pcon = preg_replace("/ /","",$pcon);
$pcon = preg_replace("/ /","",$pcon);
$pcon = preg_replace("/　/","",$pcon);
$pcon = preg_replace("/\r\n/","",$pcon);
$pcon = str_replace(chr(13),"",$pcon);
$pcon = str_replace(chr(10),"",$pcon);
$pcon = str_replace(chr(9),"",$pcon);
return $pcon;
}

function select_search($name,$tb,$fid){
    global $db;
    $title="<select name=".$name."><option value= >所有</option>";
    $r = $db->get_one("SELECT option_value FROM {$db->pre}fields WHERE name='$name' and tb='$tb'");
    $option_value=loseSpace($r["option_value"]);
    $ps = split("\*", $option_value);
    #var_dump($matchs);
    foreach ($ps as $s){
    //以*分割1|可用*=> 1, 可用
     if(!$s){
    continue;
     }
     list($num,$word) = split("\|", $s);
     $result[$num] = $word;
    }     
    foreach($result as $n => $v)
    {
    if ($n==$fid){
     $title .=" <option value=".$n." selected>".$v."</option>";
    }
    else{
     $title .=" <option value=".$n.">".$v."</option>";
    }
    }
    $title .="</select>";
    return $title;
}

$chengse = isset($chengse)?intval($chengse):0;

if($chengse) $condition .= " AND chengse=$chengse";

{select_search(chengse,sell,$chengse)}