php 문자열 자르기 간단한...한글 안 깨짐.

function han() {
global $title;
$han_num=strlen($title);
if ($han_num>50) {
$title=substr($title,0,50);
$title=$title."·······";
}
$title=str_replace("?·······","·······",$title);
return;
} // end func