In the HyperText Markup Language (HTML), a marquee is an HTML tag that causes elements contained within the tag to move across some portion of the viewable area of the web page. The HTML marquee originally was designed to allow designers to easily include a ticker-tape-style text animation, although the tag can be applied to any type of element, including images and hyperlinks. Like many HTML tags, the HTML marquee tag has several attributes that can be set to control the direction and speed of the movement, how many times the item should scroll and how much of the screen should be traversed. The HTML marquee tag was never technically part of the HTML language standard; instead, it was an extension created for a single web browser, although many other browsers eventually built in some support for the tag. The basic scrolling of an HTML marquee can easily be reproduced by using cascading style sheets (CSS) and JavaScript®, and it is the preferred method of creating the effect.
An important note about the HTML marquee tag is that it was an extension created solely for Microsoft® Internet Explorer®, without any notification to the consortium that maintains and regulates the HTML language standard. This meant the marquee feature originally would only render on one browser and had no formal standard for other browsers to implement. Most web browsers eventually implemented support for the marquee tag, mostly for compliance with existing web sites. The marquee tag officially is depreciated under the HTML language standard, however, its continued support is not guaranteed, and its continued use is discouraged.
Within a web page, the HTML marquee tag can be used to enclose some text, an image or another HTML element so the element will visibly move or scroll across a page. The default behavior is for the element to move from a non-visible position beyond the right edge of the frame to the left, and then out of view beyond the left edge of the frame. Without any other definitions, the marquee element will continually scroll in this manner for as long as the website is viewed.
Several properties can be defined to better control the behavior of an HTML marquee. The direction of the HTML marquee can be changed so objects will scroll vertically. The speed of the movement can be defined in milliseconds so the elements will move faster or slower. Most importantly, the default behavior of scrolling to and from non-visible locations can be changed so the text always appears within its scrolling area. A specific number of cycles, or loops, also can be defined so the text will only travel across the screen a certain number of times before stopping and becoming static.