DHTML Lab: HierMenus CENTRAL: Version 3.x FAQ #8 - dhtmlab.com

Frequently Asked Question #8

Entered: July 27, 1999

Every frame is a browser window and each contains a separate HTML document.

Frames are bundled together in one parent browser window for convienience. They could just as easily be separate browser windows in different parts of your screen. Now the problem should be apparent. Could you cause an HTML element or page to leave one browser window, overlap your desktop, and possibly other running programs and appear over another browser window? Can you visit a web page and have it leave the confines of the browser window and prance about on your desktop?

Of course not!

Every HTML page is self-contained. The menus are HTML elements. They must appear within the boundaries of a browser window.

In our script, we have managed to make menus appear in one frame (the main frame) while the script that creates them is in another (the nav frame). This is inter-frame, or if you will, inter-window communication. If you eliminate the border that separates these two frames, then you can create the illusion that the browser window is only one page and the menu elements are co-residing with the navigation elements. But, this is an illusion, and the best that can be accomplished with DHTML.

But what about msn.com, you say? They have menus that stradle the frame border.

An Operating System window can overlap another Operating System window. A browser window can overlap your mail client, for example. That's because they are separate programs. Some sites have menu systems that are Operating System programs. Take the msn.com example.

They have created an Active-X control. That is, a program that must be downloaded and installed on your Windows system. Once installed, it is run as any other Windows program is, so it can overlap frame borders. Such programs are Operating System-specific, browser-vendor specific, they are installed as programs on your computer, and bear no inherent relation to Web technology.

Our menu script must be as cross-browser and cross-platform as possible, using established Web technologies, like DHTML.