Ajax php jquery

I have an AJAX call on txt_RollNo's blur event to bring std_name,Class,age from database and fill it in txt_name,txt_class,txt_age.

In a single call can I have name,class,age all as a whole in array or any, how to seperate it.

$("#txt_RollNo").blur(function(){   
$.ajax({
            url:'getSudent.php',
            data:'stdID='+ $(this).val().trim(),
            success:function(array_from_php)
            {
            //but here i m receiving php array, how deal in jquery
                //$("#txt_name").val(array_from_php);
                //$("#txt_Class").val(array_from_php);
                //$("#txt_age").val(array_from_php);

            }
            })   
});

getSudent.php echos array as below

<?php   
  $qry=mysql_query("select * from students where studentID='".$_GET['std_ID']."'");   
  $row=mysql_fetch_array($qry);   
  echo $row;
?>

PHP:

<?php
  header('Content-type: application/json');
  $qry=mysql_query("select * from v_shop where shop_no='".$_GET['shopno']."'");   
  $row=mysql_fetch_array($qry);   
  echo json_encode($row);
?>

JavaScript

...
$.ajax({
    dataType: 'json',
    ...
    success:function(array_from_php){
        console.log(array_from_php); // WTF is this?

See json_encode : http://php.net/manual/en/function.json-encode.php

First in php send it as json:

echo json_encode($row);

then just treat it as any array:

$("#txt_RollNo").blur(function(){   
$.ajax({
        url:'getSudent.php',
        data:'stdID='+ $(this).val().trim(),
        dataType : 'json',
        success:function(array_from_php)
        {
           // i suggest you output the array to console so you can see it
           // more crearly
          console.log(array_from_php);
            $("#txt_name").val(array_from_php[0]);
            $("#txt_Class").val(array_from_php[1]);
            $("#txt_age").val(array_from_php[2]);

        }
        })   
});