W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
.slidecontainer {
  width: 100%;
}

.slider {
  -webkit-appearance: none;
  width: 100%;
  height: 15px;
  border-radius: 5px;
  background: #d3d3d3;
  outline: none;
  opacity: 0.7;
  -webkit-transition: .2s;
  transition: opacity .2s;
}

.slider:hover {
  opacity: 1;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 25px;
  height: 25px;
  border-radius: 50%;
  background: #04AA6D;
  cursor: pointer;
}

.slider::-moz-range-thumb {
  width: 25px;
  height: 25px;
  border-radius: 50%;
  background: #04AA6D;
  cursor: pointer;
}
</style>
</head>
<body>

<h1>Round Range Slider</h1>

<div class="slidecontainer">
  <input type="range" min="1" max="100" value="50" class="slider" id="myRange">
  <p>Value: <span id="demo"></span></p>
</div>

slider.oninput = function() {
  output.innerHTML = this.value;
}
</script>

</body>
</html>

​x
 
<!DOCTYPE html><html><head><meta name="viewport" content="width=device-width, initial-scale=1"><style>.slidecontainer {  width: 100%;}​.slider {  -webkit-appearance: none;  width: 100%;  height: 15px;  border-radius: 5px;  background: #d3d3d3;  outline: none;  opacity: 0.7;  -webkit-transition: .2s;  transition: opacity .2s;}​.slider:hover {  opacity: 1;}​.slider::-webkit-slider-thumb {  -webkit-appearance: none;  appearance: none;  width: 25px;  height: 25px;  border-radius: 50%;  background: #04AA6D;  cursor: pointer;}​.slider::-moz-range-thumb {  width: 25px;  height: 25px;  border-radius: 50%;  background: #04AA6D;  cursor: pointer;}</style></head><body>​<h1>Round Range Slider</h1>