ajax error handler http://www.jquery4u.com/ajax/jquery-ajax-error-handling-function/

errorHandler.js

$.ajaxSetup({
  error: function(jqXHR, exception) {
    if (jqXHR.status === 0) {
        alert('Not connect.\n Verify Network.');
    } else if (jqXHR.status == 404) {
        alert('Requested page not found. [404]');
    } else if (jqXHR.status == 500) {
        alert('Internal Server Error [500].');
    } else if (exception === 'parsererror') {
        alert('Requested JSON parse failed.');
    } else if (exception === 'timeout') {
        alert('Time out error.');
    } else if (exception === 'abort') {
        alert('Ajax request aborted.');
    } else {
        alert('Uncaught Error.\n' + jqXHR.responseText);
    }
  }
});