I had to actually see a demonstration to believe what position:fixed as an attribute and value for an html element in a style sheet can do:
[ source ]
<!DOCTYPE html>
<html>
<head>
<style>
div.fixed {
position: fixed;
bottom: 10px;
right: 10px;
width: 700px;
border: 5px solid lightskyblue;
}
</style>
</head>
<body>
<h2>Illustrating position: fixed;</h2>
<p>An html element with <i>position: fixed;</i> is positioned relative to the present state of the browser content:</p>
<div class="fixed">
This div element has <i>position: fixed</i>, which means it always stays in the same location in the browser even if the page scrolls up or down;
</div>
</body>
</html>
