Checkbox nelze zaškrtnout

<input type='checkbox' name='selected_photo[]' class='selected_photo' value='1'>
<input type='checkbox' name='selected_photo[]' class='selected_photo' value='2'>
<input type='checkbox' name='selected_photo[]' class='selected_photo' value='3'>

$(document).ready(function(){        
    $("input.selected_photo").click(function(){    
        var value_element = $(this).attr("value");
        $.ajax({  
            type: "POST", 
            url: 'admin_gallery_ajax.php', 
            data: {
                selected_photo:    value_element
            },
            complete: function(data){                   
                $("div#ajax_mass_deletion").html(data.responseText);    
            }  
        }); 
        return false;
    });           
});