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jQuery: Global AJAX Events for Start, Stop, Complete, or Error jQuery: Global AJAX Events for Start, Stop, Complete, or Error

Published on Feb 18, 2019 by Jamie Munro

When your website contains a lot of AJAX requests using jQuery and you want to add a global event at the start or finish of the AJAX request, e.g. add a spinning icon, or handle all AJAX errors in a particular fashion.

The jQuery library provides multiple events for ajax event handlers. This article will focus on ajaxStart and ajaxError.




These events are a great way to easily add uniformity to how you handle AJAX requests. For example, perhaps you have a very busy website that on occasion an AJAX request doesn't complete and an error is returned. When there is an error, you could show a standard error dialog asking the user to try again.

Configuring ajaxError




$(document).ajaxError(function() {
$("#error").show();
});


Configuring ajaxStart



Or if you want to always show a loading element when the ajax request starts and hide it when it's done you could do the following:


$(document).ajaxStart(function() {
$("#loading").show();
});

$(document).ajaxStop(function() {
$("#loading").hide();
});


If you want to get more information about the AJAX request, you could update the above calls to pass a variable in the function:


$(document).ajaxStart(function(e) {
$("#loading").show();
});

$(document).ajaxStop(function(e) {
$("#loading").hide();
});


Then you can use the variable e to access some of the properties. For example: console.log(e.currentTarget.activeElement); Will tell you what element made the AJAX request. Inside of Firebug if you perform a console.log(e); you can see all of the properties available of that object.

Tags: jquery | JavaScript | jQuery | AJAX

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