On January 15th, jQuery updated to version 1.9.0. Customers that are using the jquery-latest.js will automatically use the updated version. The script looks like the following:
If you are using jquery-latest.js for your jQuery, you will want to switch back to the old version by linking the script to the version 1.8.3 like the following.
If you are a developer, you can update the code for the jQuery by editing the code in the head section of your site. If you are not a developer and are not comfortable with editing code, then you will want to contact your developer.