If you have recently added your site to the Cloudflare service and set the caching to aggressive you may lose some javascript functionality on your site. One such example is in WordPress if you are using a Woo Theme one of the casualties of aggressive caching may be the slider images simply stop sliding or a Facebook like box no longer appears in the sidebar.

To fix this, login to your Cloudflare account and go to the Cloudflare Settings >> Performance Settings and set the Rocket Loader setting to manual or off.

This will fix the issue. Rocket Loader may also cause a number of other issues.

The Rocket Loader function is a beta product and attempts to load your web pages javascript files at the same time resulting in decreasing page load times – but can also causing some conflicts, as in this case – report a bug to Cloudflare as they strive to make this functionality more stable.