My PHP script is not returning data to AJAX script : <p>PHP script:- </p>

<pre><code>&lt;?php
header('Access-Control-Allow-Origin: *');
echo "Done";
?&gt;
</code></pre>

<p>AJAX script:-</p>

<pre><code>$(document).ready(function(){
$('#submit').click(function(){
    $.ajax({
        type : "POST",
        url : "http://127.0.0.1/ionic/retri.php",
        success : function(data){
            alert(data);
            $('#card').text(data);
        }
    })
 });
});
</code></pre>

<p>HTML:-</p>

<pre><code> &lt;button id="submit" class="button button-block button-positive"&gt;
     Submit
    &lt;/button&gt;
    &lt;div class="card"&gt;
      &lt;div id="card" class="item item-text-wrap"&gt;

      &lt;/div&gt;
    &lt;/div&gt;
</code></pre>

<p>I have just started learning AJAX and wrote this script just to echo simple text and update the html div but I am not getting any output. </p>
