<!DOCTYPE html>
<html>
<body>
<p style="background:red;min-width:600px;" id="myP">The minimum width of this paragraph is set to 600px.</p>
<button type="button" onclick="myFunction()">Return min width</button>
<script>
function myFunction() {
alert(document.getElementById("myP").style.minWidth);
}
</script>
</body>
</html>