Tooltips - The "title" attribute on its own is not a compliant solution

It has been common practice on the web to use the HTML "title" attribute for users to find out more infomation about an icon's purpose or details about points on a graph. Unfortunately these tooltips only appear for mouse users on hover, they do not appear on keyboard focus. This means if you intend to have tooltips you should invest in a solution that works for both hover and focus.

Examples:

This is a non-accessible example using the standard title attribute to make a tooltip - Hover the word - submarine. Hover with your mouse and also try tabbing with your keyboard to it.