<!DOCTYPE html>
<html>
<body>
<p>Peter's score: <meter id="myMeter" value="0.3" high="0.9" low="0.1" optimum="0.5"></meter></p>
<p>Click the button to change the value of the optimum attribute of the gauge above.</p>
<button onclick="myFunction()">Try it</button>
<p><b>Note:</b> The optimum property is not supported in Internet Explorer and Safari 5 (and earlier versions).</p>
<p id="demo"></p>
<script>
function myFunction() {
document.getElementById("myMeter").optimum = "0.7";
document.getElementById("demo").innerHTML = "The value of the optimum attribute was changed from '0.5' to '0.7'.";
}
</script>
</body>
</html>