I am working with jquery and php, Right now i have "Edit" button but whenever i am clicking on button i am getting "alert" twice instead of one time, Here is my html code(inside php tag)

<?php
$PostComment2='<div class="button1'.$CommentID.'">
<span  name="MaxValue" value='.$CommentID.' data-val='.$CommentID.' id="MaxValue" class="edit_post_comment">
Edit2
</span></div>';
?>

Here is my script

<script>
      $(document).ready(function(){
      $(document).on('click','.edit_post_comment',function(e){
      e.preventDefault(); 
      alert('Hello world');
      //further code...
    });
}); 
</script>

How can i alert one time only instead of twice,Where i am wrong ?