Web site - 207Chapter 15 .Generic HTML Element Objects event handler
207Chapter 15 .Generic HTML Element Objects event handler can be associated with individual elements of a document in the Windows version, you can create a context-sensitive help system. However, if the focus is in the Address field of the browser window, you cannot intercept the event. Instead, the browser s Help window appears. Example (with Listing 15-40) on the CD-ROM Related Items: window.showHelp(), window.showModalDialog() methods. onKeyDown onKeyPress onKeyUp NN2 NN3 NN4 NN6 IE3/J1 IE3/J2 IE4 IE5 IE5.5 Compatibility When someone presses and releases a keyboard key, a sequence of three events fires in quick succession. The onKeyDown event fires when the key makes its first contact. This is followed immediately by the onKeyPress event. When contact is broken by the key release, the onKeyUpevent fires. If you hold a character key down until it begins auto-repeating, the onKeyDownand onKeyPress events fire with each repetition of the character. The sequence of events can be crucial in some keyboard event handling. Consider the scenario that wants the focus of a series of text fields to advance automatically after the user enters a fixed number of characters (for example, date, month, and two-digit year). By the time the onKeyUp event fires, the character associated with the key press action is already added to the field and you can accurately determine the length of text in the field, as shown in this simple example: