Edit in JSFiddle

<section>
    <h2>Task Progress</h2>
    <p>Progress: <progress id="p" max=100><span>0</span>%</progress></p>
</section>

var progressBar = document.getElementById('p');
function updateProgress(newValue) {
progressBar.value = newValue;
progressBar.getElementsByTagName('span')[0].textContent = newValue;
}