How to use migrate jQuery plugin?

The jQuery Migrate plugin is designed to help developers update and migrate their code to newer versions of jQuery. It serves as a bridge between older jQuery code and newer jQuery versions, providing information about deprecated or removed features and helping to identify potential issues in the code. Here's how to use the jQuery Migrate plugin:

Include the jQuery Migrate Plugin

First, you need to include the jQuery Migrate plugin after including the jQuery library in your HTML file.

<script src=""></script> <script src=""></script>

Review Browser Console

  1. Once you've included the Migrate plugin, open your web page in a browser and access the browser's developer console.
  2. You will see warnings and messages in the console related to deprecated or removed features in the version of jQuery you are using.

Update Your Code

  1. Review the console messages carefully, and update your code according to the guidance provided by the Migrate plugin.
  2. It will often indicate which parts of your code need attention, such as deprecated methods, event handling changes, or other potential issues.


After making the necessary updates, thoroughly test your application to ensure it works as expected with the newer version of jQuery.


Suppose you have jQuery code that uses the .size() method, which was deprecated in jQuery 1.8 and removed in later versions. The Migrate plugin will generate a console warning like this:

JQMIGRATE: jQuery.fn.size() is deprecated and removed; use the .length property

You can then search your code for usages of .size() and update them to use .length instead.

// Before var count = $("div").size(); // After (Updated) var count = $("div").length;


The jQuery Migrate plugin is a valuable tool for maintaining and upgrading your jQuery-based projects to newer versions of jQuery while ensuring backward compatibility with older code. It helps developers identify and address potential issues efficiently.