function rn(from, to) { return ~~(Math.random() * (to - from + 1)) + from; } function rs() { return arguments[rn(1, arguments.length) - 1]; } function boxShadows(max) { let ret = []; for (let i = 0; i < max; ++i) { ret.push(` ${ rn(1, 100) }vw ${ rn(1, 100) }vh ${ rn(20, 40) }vmin ${ rn(1, 20) }vmin ${ rs('#F52D75', '#CCBD4F', '#32497F', '#EB4377') } `) } return ret.join(','); } const cloud = document.querySelector('#cloud'); function update() { cloud.style.boxShadow = boxShadows(120); } window.addEventListener('load', update); document.addEventListener('click', update);