jQuery migrate

jQuery migrate
Written by Sagar RabidasJanuary 5, 2022
11 min read
Sagar Rabidas

Software Developer

In this blog, we will discuss jQuery migrate.

jQuery migrate:-

In jQuery, migrate is defined as a javascript library for upgrading libraries such as jquery, making it quite simple for restoring the APIs whilst upgrading from an older model to a newer model as those APIs had been eliminated during the up-gradation to the more recent model of jquery. In well-known, it's far described as a library that makes jquery without difficulty migrate from older version to more modern version without disposing of or deleting any API's inside the jquery libraries and also throws a few extra warnings inside the browser console if there is any jquery API's that have been utilized in older version were eliminated or deprecated.

Working of jQuery migrate:-

In this text, we can see jquery migrate, which is often a javascript library used in jquery to make it clean for jquery libraries to improve or migrate from one version (older model) to any other model (newer version). It's miles defined as a library this is used for retaining the compatibility of jquery code or jquery libraries, and this is mainly advanced for the jquery variations older than the 1. Nine versions, which could not directly maintain all the capabilities and behaviors the same as within the preceding version even after upgrading or migrating to a more recent version. It is a kind of plug-in inside the latest website design software program together with WordPress three.6 onwards; this jquery migration is mechanically blanketed in almost all of the web pages.

An alternative to this plug-in there are different up-to-date plug-ins and topics wherein jquery migrate is of no need within the frontend improvement of internet pages, and therefore the jquery code can be deleted correctly, if you want to, in turn, assist the browser to load the website quicker than earlier. This jquery migrate plug-in via default is found in many web pages, and if we've updated topics and plugins, we can delete this plug-in the use of another plug-in named “cast off jquery migrate competently”, however, if we're in the dilemma of whether or not to do away with this or no then that also may be carried out the usage of configuration command which includes wp –config.Php in which we can see within the console as we browse web sites. Such a lot of builders endorse removing such plug-in because it takes loads of space and makes the site load slowly.

If we need to feature jquery migrate in our jquery codes, then when we write the code for jquery in HTML shape, we define a <script> tag wherein we upload the source for jquery codes to run using the jquery.Com link, and after this script tag, we need to define any other script tag wherein we can define this jquery migrate files, and that is completed as follows.


<script src = " https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js" > </script>
<script src="https://code.jquery.com/jquery-migrate-3.3.1.js"> </script>

The plug-in is a kind of upgrading tool for alerting warning messages which would help developers to identify and debug the errors before migrating from one version of jQuery to a newer version of jQuery where these messages will be displayed on the browser console only once for each unique warning messages, and the messages start with “JQMIGRATE” when this plugin throws a warning message which also gives what caused this warning to appear ad also sometimes it will give the solution for such warning message displayed.

Now let us see a few warning messages that can be seen ad how they will be displayed:

Suppose if we want to use $.browser, and it is supported only by using the plug-in. So when we try to remove this $.browser, it will display a warning message in the browser, as shown below.


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<script src=
<script src="https://code.jquery.com/jquery-migrate-3.3.1.js"></script>
<h1 style = "background-color:red" >
$(document).ready(function() {
var migratedef ;
if ($.browser == migratedef) {
msg = [];
msg.push("WARNING: This browser does not support the $.browser variable as the jquery you using is upgraded to newer version.");
msg.push("Install jquery-browser: https://raw.github.com/jquery/jquery-browser/master/src/jquery.browser.js");
return $;

jQuery migrate messages start with JQMIGRATE few of them are as below:

  1. Its warning message will be displayed when any jquery object element name is written in some other cases where jquery 3.0 version takes camel cases such if the element name was “jqfunc” then this would give a warning message as “JQMIGRATE: jquery. data() always sets or gets camelCase names” so to debug this warning we have to rename it as “jqFunc” as the element name.
  2. The older versions of jquery.param() function which is serialization method that uses ajax module such as jquery.ajax settings.traditional. But when we are upgrading to a newer version of jquery 3.0 and above, this module is independent of jquery’s ajax module; this is usually used for form-data encoding, and the message would be as “JQmIGRATE: jquery. param() no longer uses jquery. ajax settings. traditional”. So to avoid such a warning message, we need to pass it explicitly if we are using this traditional flag.
  3. In older versions of jQuery, there was the jquery.swap() method, which is used for exchanging or swapping of CSS properties which are now removed in the newer versions of jQuery such as jquery 3.0 so when we are trying to upgrade to a newer version using jQuery migrate, it would display a message as “JQMIGRATE: jquery. swap() is undocumented and deprecated” so to avoid getting this message we have to avoid calling this jquery.swap() method.

Similarly, many such jQuery migrate warning messages will be shown when we are trying to migrate from an older to a newer version of jQuery if we have a plug-in.


We conclude that the jQuery migrate is a library in JavaScript which is defined as an upgrading tool or library in jquery which is defined as a library that gives a warning message instead of errors which can be used to restore any features of the jQuery with an older version when upgrading or migrating to the newer versions. In this article, we saw a few warning jQuery migrate messages that start with “JQMIGRATE”. We saw the message and how to avoid such migrate warning messages in jQuery newer version when upgrading from older jQuery versions.

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Sagar Rabidas
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made with by Abhishek & Priyanka Jalan