php输出json数组和json

 function getCitys(){

     $provinceid=trim($_REQUEST['province']);

     $citylist=M('city')->field('cityid,cityname')->where('provinceid ='.$provinceid)->select();         //这个方法输出json数组 

     //echo json_encode($citylist);

     $temp='{';

     for ($i=0;$i<count($citylist);$i++){

     if($i==count($citylist)-1){

     $temp=$temp.'"'.$citylist[$i]['cityid'].'":"'.$citylist[$i]['cityname'].'"';

     }else{

     $temp=$temp.'"'.$citylist[$i]['cityid'].'":"'.$citylist[$i]['cityname'].'",';

     }

     }

     $temp=$temp.'}';

     echo  $temp;

    }