This is a DHTML replacement for popup windows created with window.open() JavaScript function. DHTML popup window has the following advantages over the standard popups: it has fully customizable design; it will not be blocked by popup blocking software; unlike standard popups, it will not be sent to back when you click on the main window. You have many options to position DHTML popup window: relative to the browser window, relative to the mouse pointer, relative to an HTML element, or you can keep its current position. You can move and close DHTML popup window just the same way as a window in a Windows application.