index.html

<div id="cont" data-precent="100">
  <svg id="svg" width="200" height="200" viewPort="0 0 100 100" version="1.1" xmlns="http://www.w3.org/2000/svg">
    <circle r="90" cx="100" cy="100" fill="transparent" stroke-dasharray="565.48" stroke-dashoffset="0"></circle>
    <circle id="bar" r="90" cx="100" cy="100" fill="transparent" stroke-dasharray="565.48" stroke-dashoffset="0"></circle>
  </svg>
</div>
<label for="percent">Type a percent!</label>
<input id="percent" name="percent">

index.js

const userInput = document.querySelector('#percent');
userInput.addEventListener('change', function() {
const inputVal = parseInt(this.value);
const progress = Number.isNaN(inputVal) ? 0 : Math.max(0, Math.min(100, inputVal));
const circle = document.querySelector('#svg #bar');

const r = circle.attributes.r.value;
const c = Math.PI*(r*2);
const precent = ((100-progress)/100)*c;
circle.style = `stroke-dashoffset: ${precent};`
const parent = document.querySelector('#cont');
console.log(parent.dataset)
parent.dataset.precent = progress;

style.css

#svg circle {
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 1s ease;
  stroke: #666;
  stroke-width: 1em;
}
#svg #bar {
  stroke: #FF9F1E;
}
#cont {
  display: block;
  height: 200px;
  width: 200px;
  margin: 2em auto;
  position: relative;
}
#cont:after {
  position: absolute;
  display: block;
  height: 160px;
  width: 160px;
  left: 50%;
  top: 50%;
  content: attr(data-precent)"%";
  margin-top: -80px;
  margin-left: -80px;
  border-radius: 100%;
  line-height: 160px;
  font-size: 2em;
}

input {
  color: #000;
}


/* Make things perty */
body {
  height: 100%;
  text-align: center;
 }