When you set a default scripting language, you use the MIME content type for scripts. You can override the default scripting language at any point in your pages with the script element, but note that the specification no longer recommends that you use the language attribute with it. While all this gets sorted out, it is probably a good idea to know that the type attribute is valid but doesn't have to be used just yet. Another important change for Web scripting is that most HTML elements now support a wide range of event attributes. Events occur automatically when a certain condition exists.
Some events are user-driven, by the press of a key or a click of the mouse.
Others are browser-driven, such as when the browser finishes loading an image. Event attributes allow you to specify the conditions you want an element to detect. For example, you can create clickable cells in tables, paragraphs of text that light up when the mouse is over them, and a whole lot more. There are several ways to work with events. You can use event attributes, such as onclick or onkeypress, to detect the event and then pass it off to a script function.