JavaScriptless Tool Tips
Tooltips are a useful feature that can be used to elaborate on information without creating another page or linking to another source. It presents the user with immediate results. There are a variety of tooltips available that utilize JavaScripts advantages. Even though most are widely compatible with browsers there is still a small percentage of users that would not see the tooltip when activated with JS.
To solve this problem a CSS solution can be deployed that would work everywhere. There are no bells and whistles but if you require them I would suggest going the JavaScript route.