HTML max-width

<!DOCTYPE html>
<html>
<head>
<style>
div.ex1 {
    width:500px;
    margin: auto;
    border: 3px solid #73AD21;
}

div.ex2 {
    max-width:500px;
    margin: auto;
    border: 3px solid #73AD21;
}
</style>
</head>
<body>

<div class="ex1">This div element has width: 500px;</div>
<br>

<div class="ex2">This div element has max-width: 500px;</div>

<p><strong>Tip:</strong> Drag the browser window to smaller than 500px wide, to see the difference between
the two divs!</p>

</body>
</html>