<marquee> elements are deprecated and must not be used
<marquee> elements must not be present because they are deprecated, increase difficulty for users with limited dexterity, and are distracting for users with cognitive or attention deficits.
The Algorithm, in Simple Terms
<marquee>element is not used
Why this is Important
<marquee> element creates scrolling text that is difficult to read and click on. Beyond that, it can be distracting to viewers, especially to those with low vision, cognitive disabilities, or attention deficits.
People with attention deficits or cognitive disabilities could become distracted by content that scrolls. If scrolling content contains links, people with limited fine motor abilities may not be able to click on the links accurately. Users with visual impairments may not be able to see the scrolling text with enough acuity to know what the content says.
How to Fix the Problem
Deprecated elements which are presentational in nature have typically been replaced by cascading style sheets (CSS), and their use may interfere with the ability of assistive technologies to properly render content.
<marquee> elements, even if they are empty.
Example of What To Remove
The following is code for scrolling marquee text with links, followed by the rendered display output:
<marquee behavior="scroll" direction="left"> Frisbeetarianism is the <a href="http://en.wikipedia.org/wiki/Belief">belief</a> that when you <a href="http://en.wikipedia.org/wiki/Death">die</a>, your <a href="http://en.wikipedia.org/wiki/Soul">soul</a> goes up on the <a href="http://en.wikipedia.org/wiki/Roof">roof</a> and gets stuck.</marquee>
- HTML 4