jQuery AJAX Error Handling (HTTP Status Codes)

Check out jQuery.ajaxError()

It catches global Ajax errors which you can handle in any number of ways:

if (jqXHR.status == 500) {
  // Server side error
} else if (jqXHR.status == 404) {
  // Not found
} else if {
    ...

Alternatively, you can create a global error handler object yourself and choose whether to call it:

function handleAjaxError(jqXHR, textStatus, errorThrown) {
    // do something
}

$.ajax({
    ...
    success: function() { ... },
    error: handleAjaxError
});