jQuery: Handle fallback for failed AJAX Request

Question

Can jQuery provide a fallback for failed AJAX calls? This is my try:

function update() {     var requestOK = false;      $.getJSON(url, function(){         alert('request successful');         requestOK = true;     });      if (!requestOK) {         alert('request failed');     } } 

Unfortunately, even if the callback function of the $.getJSON() method is called, i get the message 'request failed', before the callback function has the opportunity to set the requestOK variable. I think it's because the code runs in parallel. Is there a way to handle such situations? I thought about chaining or some way of waiting for the AJAX request, including its callback function. But how? Does anyone know how to do that?

Answer 1

You will need to either use the lower level $.ajax call, or the ajaxError function. Here it is with the $.ajax method:

function update() {   $.ajax({     type: 'GET',     dataType: 'json',     url: url,     timeout: 5000,     success: function(data, textStatus ){        alert('request successful');     },     fail: function(xhr, textStatus, errorThrown){        alert('request failed');     }   }); } 

EDIT I added a timeout to the $.ajax call and set it to five seconds.