Json code is not working when i am including wp-load.php in my file

i am newbie in wordpress. i have just started with wordpress before some day.

i am doing here ajax request to contact.php file. everything is working fine. but i am facing problem is when i am including wp-load.php the json data is not coming/printing.

if i am not including wp-load.php then JSON data is coming/printing. i don’t what’s going wrong with my file if i am including wp-load.php file.

myscript file

var name=$("#firstname").val();
           var email=$("#useremail").val();
           var contact=$("#mobile").val();
           var type=$("#type").val();
           var msg=$("#message").val();
           var data = { 'name': name, 'email' : email, 'contact' : contact, 'type' : type, 'msg' : msg };
           $.ajax({
               url : '/theme_demo/wp-content/themes/bootstrap/contact.php',
               type : 'POST',
               data : {result:JSON.stringify(data)},
               success : function (msg)
               {
                  alert(msg);
               }
           })

contact.php

<?php
 require_once('../../../wp-load.php' );

 if(isset($_POST['result']))
 {
   global $wpdb;
   $data= $_POST['result'];
   $data = json_decode($result,true);

    echo $data['name'];
 }
?>

here if i won’t include this require_once(‘../../../wp-load.php’ ); then it’s working but i am including it then json is not responding.

i want to include require_once(‘../../../wp-load.php’ ); it because i am interacting with database so..

can you suggest me what am i doing wrong in my code?

Thanks in advance..