Text displayed on a computer with references hyperlinks to other text that the reader can immediately follow, usually by a mouse click or key-press sequence. This can occur within a document residing on the user’s hard drive or anywhere in the World Wide Web. Apart from running text, hypertext may contain tables, images and other presentational devices. Other means of interaction may also be present, e.g. a bubble with text may appear when the mouse hovers somewhere, a Video clip may be started and stopped, or a form may be filled out and submitted.