$.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.'"})';
?>