即使我点击Stay on Page，event fire window.beforeunload

$(window).bind('beforeunload', function() {

    return "Content will be deleted";
    Cookies.remove('title');
    Cookies.remove('description');
    Cookies.remove('imageCollection');
    Cookies.remove('imageIdCollection');

     $.ajax({
       url: "<?php echo base_url(); ?>myController/myFunction",
       type:'POST',
             }).done(function (data){
                 $("#display").html(data);
                 $('#loadingmessage').hide();

             });

         });
$(window).bind('beforeunload', function() {