HTMLProgressElement: position 屬性

Determinate Progress bar: <progress id="pBar"></progress> Position:
<span>0</span>

const pBar = document.getElementById("pBar");
const span = document.getElementsByTagName("span")[0];

pBar.max = 100;
pBar.value = 0;

setInterval(() => {
  pBar.value = pBar.value < pBar.max ? pBar.value + 1 : 0;

  span.textContent = pBar.position;
}, 100);