Nonstandard. Defines a scrolling area (usually horizontal) of text.
No, really. don’t use it.
The default width of the MARQUEE element is equal to the width of its parent element. When a MARQUEE is in a TD that does not specify a width, you should explicitly set the width of MARQUEE. If neither the MARQUEE nor the TD has a width specified, the marquee is collapsed to a 1-pixel width. To create a vertically scrolling marquee, set its scrollLeft property to 0. To create a horizontally scrolling marquee, set its scrollTop property to 0, overriding any script setting. The scrollLeft and scrollTop properties are read-only while the marquee is scrolling. When not scrolling, scrollLeft is read/write for a marquee set to scroll horizontally and scrollTop is read/write for a marquee set to scroll vertically.
Microsoft Developer Network: [Windows Internet Explorer API reference Article]