as the marquee element has been removed from html5 (which is probably a good thing) its now unsupported, but you can use css and keyframes to recreate it. Yay..

CSS Marquee Demo

You can change the speed by modifying this line:

animation: marquee 5s linear infinite;

the lower the s the faster it goes

code

<div class='marquee'>
	<p>Some Marquee Text</p>
</div>

<style>
.marquee {
    width: 100%;
	line-height: 40px;
	background-color: #444;
	color: #FFF;
    white-space: nowrap;
    overflow: hidden;
    box-sizing: border-box;
}
.marquee p {
    display: inline-block;
    padding-left: 100%;
    animation: marquee 5s linear infinite;
}
@keyframes marquee {
    0%   { transform: translate(0, 0); }
    100% { transform: translate(-100%, 0); }
}
</style>

You can go the other way as well... if you like

Just remove the - from the translate and change the padding to right rather than left

Code Right

<div class='marquee-right'>
	<p>Some Marquee Text</p>
</div>

<style>
.marquee-right {
    width: 100%;
	line-height: 40px;
	background-color: #444;
	color: #FFF;
    white-space: nowrap;
    overflow: hidden;
    box-sizing: border-box;
}
.marquee-right p {
    display: inline-block;
    padding-right: 100%;
    animation: marqueeright 5s linear infinite;
}
@keyframes marqueeright {
    0%   { transform: translate(0, 0); }
    100% { transform: translate(100%, 0); }
}
</style>

We can add a pause to the animation when the mouse is over it by adding the following

.marquee:hover p {
	animation-play-state: paused;
}
.marquee-right:hover p {
	animation-play-state: paused;
}