It seems my code is NEVER passing data to my php script. I'm using xamp as "server"...

here is how I coded :

1. $.ajax({
           url: "phpscript.php",
           type : 'POST',
         contentType: "application/json; charset=utf-8",
         data:{user_id:'user_id'},
         dataType : 'text',
          success: function(result){
          console.log(result);}});

My php is soooo simple

1. <?php
   $value = array();

   $value['id'] = 'ok' . $_POST['user_id'];

   echo json_encode($value);
   ?>

console.log(result) says : 

2. <br />
3. <b>Notice</b>:  Undefined index: user_id in <b>D:\xampp\htdocs\myapp\phpscript.php</b> on line <b>9</b><br />
4. {"id":"ok"}

just as if $.ajax was NEVER sending it "data" when calling the php script...

Any help fixing that !?  (ps : please don't tell me isset() or empty() because This code is suppose to be (or MUST) populating $_POST with data ....