$.ajax({
    url: 'http://linktodatajson',
    type: 'POST',
    dataType: 'json',
    data: { email: "mypost@lala", password: "11111"},
    success: function(data){
    console.log(data);
    token = data.token;
  },
});<?php
$true_email='mypost@lala';
$true_pass='11111';
$token="897gfs9s8d7f89gd7gf";
$email=$_POST['email'];
$password=$_POST['password'];
if (($email==$true_email) && ($true_pass==$password)) echo '({"token":"'.$token.'"})';
?>