It is enabled in your conference's
Make sure you insert these lines after loading any stylesheets.
When enabled, some Act features will take advantage of JQuery's Ajax support to provide an enhanced user experience by eliminating page reloads or explicit change submission.
Alternatively, you can load jquery from Google's content delivery network.
The benefits are Google's fast response time and a gzip-encoded response: currently about 17 KB as opposed to 55 KB when using Act's version. The downside is that you might need to keep track of which version of jQuery is certified to work with Act.