Wordpress - JQuery Ajax - erfolgreiche Ausgabe der Response aber trotzdem -1 am Ende

<form id='my_form'>  
<input type='text' value='TEST' size='50' name='data1'><br>  
<input type='button' value='Report' id='submit_form'>  


 jQuery('#submit_form').click(function(){  

        var str = jQuery("#my_form").serialize();  
        
	jQuery.ajax({
  		url: 'http://localhost/wordpress/wp-admin/admin-ajax.php',  
  		type: 'POST',  
  		data: 'action=handle_ajax&'+ str,  
  		
  		error: function() {
    		alert('fehler');  
  		},
  		success: function(response) {
    		alert(response);
  		}	
	});
});	 

 add_action('wp_ajax_nopriv_handle_ajax, 'handle_ajax_func');  
 
 function handle_ajax_func() {

    echo $_POST['data1'];  

 }