You can load jQuery from a CDN with the following layout XML, placed within your `<default>` handle in local.xml or other layout XML file:

    <reference name="head">
        <block type="core/text" name="head.jquery">
            <action method="setText">
                <text><![CDATA[<script src="//ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script><script>window.jQuery||document.write('<script src="//ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js">\x3c/script>');</script><script>jQuery.noConflict();</script>]]></text>
            </action>
        </block>
    </reference>

Replace the version/URL accordingly.

## Is it worthwhile?

Whether or not you will get much of doing this is debatable.

In my experience I've found that it's generally better not to do this; jQuery's size after gzipping is pretty minimal compared to things like product images, and it can slow down local development if you have connection problems while working.

*Note: code snippet taken from answer to [this question][1], which appears to be valid.*


  [1]: https://magento.stackexchange.com/questions/3523/google-cdn-jquery-with-local-fallback-in-magento-layout-xml