Tryit Editor v1.8

Source Code:

<!DOCTYPE html>
<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js">
</script>
<script>
$(document).ready(function(){
  $("p").on("custom.someNamespace",function(event){
    alert(event.namespace);
  });
  $("p").click(function(event){
    $(this).trigger("custom.someNamespace");
  });  
  $("button").click(function(){
    $("p").off("custom.someNamespace");
  });
});  
</script>
</head>
<body>

<p>Click on this paragraph.</p>
<button>Remove namespace</button>

</body>
</html>

Result:

W3Schools.com - Try it yourself

Edit the code above and click "Submit Code" to see the result.