preg_replace()乱码,该怎么处理

$search_input=$_REQUEST["search_input"];
$search_input = preg_replace('/\s(?=\s)/','', $search_input);
$search_array=explode(" ",$search_input);

	if (is_array($search_array)){
		$search_array=implode("|",$search_array);
	}
	$clientNumber=preg_replace("/($search_array)/i","\\1",$clientNumber);
	$clientTime=preg_replace("/($search_array)/i","\\1",$clientTime);



echo "$i";