mysql php无刷新三级联动菜单

$sql="select * from ptypes where sid = 0 and ssid =0";
$result=mysql教程_query($sql,$conn) or die("查询数据库教程出错1");
while($row=mysql_fetch_object($result))
{
   $i=0;
   $rs2="";
   $sql2="select * from ptypes where sid='".$row->id."'";
   $result2=mysql_query($sql2,$conn) or die("查询数据出错2");
   while($row2=mysql_fetch_object($result2))
   {
       if ($i==0){
        $t="";
    }else{
        $t=",";
    }
       $rs2.=$t."{txt:'".$row2->title."',val:'".$row2->id."'}n";
    $n=0;
    $rs3="";
    $sql3="select * from ptypes where ssid='".$row2->id."'";
    $result3=mysql_query($sql3,$conn) or die("查询是数据库出错3");
    while($row3=mysql_fetch_object($result3))
    {
       if ($n==0)
    {
       $t1="";
    }else{
       $t1=",";
    }
    $rs3.=$t1."{txt:'".$row3->title."',val:'".$row3->id."'}n";
    $n=1;
    }
   
    echo("sidArr['".$row2->id."']=[".$rs3."];");
    $i=1;
   }
  
   echo("sidArr['".$row->id."']=[".$rs2."];");
}
?>
function setCity(province) {
       
         removeOptions(document.getElementById('sid'));
   removeOptions(document.getElementById('ssid'));
   setSelectOption('sid', "", '-请选择-');
   setSelectOption('ssid', "", '-请选择-');
         if (!sidArr[province] || sidArr[province]==""){
      
             document.getElementById('sid').disabled=true;
    document.getElementById('ssid').disabled=true;
   }else{
       document.getElementById('sid').disabled=false;
    document.getElementById('ssid').disabled=false;
             setSelectOption('sid', sidArr[province], '-请选择-');
   }
}
function setssid(province) {
         removeOptions(document.getElementById('ssid'));
   setSelectOption('ssid', "", '-请选择-');
         if (!sidArr[province] || sidArr[province]==""){
    document.getElementById('ssid').disabled=true;
   }else{
       document.getElementById('ssid').disabled=false;
             setSelectOption('ssid', sidArr[province], '-请选择-');
   }
}

  
   -请选择-
      $sql="select * from ptypes where sid=0 and ssid = 0";
   $result=mysql_query($sql,$conn) or die("返回数据记录出错!");
   while($row=mysql_fetch_object($result))
   {
       echo ("".$row->title."");
   }
   ?>
一级
  
    
-请选择-
二级

    
-请选择-
三级