.div {
background: red;
width: 100px;
height: 100px;
filter: opacity(50%);
}<input type="range" min="0" max="100" step="10"> const div = document.querySelector('.div');
let range = document.querySelector('#range');
range.addEventListener("input", function(e) {
div.style.filter = `opacity(${e.target.value}%)`
});filter: blur(3px);