Debug your code by using keywords
debugger;
or
alert('something');
.
Something as below.
success: function (data, textStatus) {
if (data.redirect) {
debugger;
alert(data.redirect);
window.location.href = data.redirect;
}
else {
$("#notification").replaceWith(data.form);
}
},
You may also refer below link discussing similar problem, where questioner solved the problem by specifying correct link/url.
http://forum.jquery.com/topic/jquery-jquery-location-href-or-load-problem