Most objects have events, not just HTML controls. For example tags such as <table>, <tr>, <td>, <a>, and <strong> also have events.
We can use events to dynamically change the CSS used on a Web page. This example uses the onMouseOver and onMouseOut event of the <strong> tag to change the class used a tag. Moving over the words "Change Color of Text and Body" will change the document color to black or orange.
Change Color of Text and Body