如何使用 JavaScript 实现一个简单的图片放大镜效果？

/* 如何使用 JavaScript 实现一个简单的图片放大镜效果？ */
var img = document.createElement('img');
img.src = 'https://www.baidu.com/img/bd_logo1.png';
img.style.width = '100px';
img.style.height = '100px';
img.style.position = 'absolute';
img.style.top = '0';
img.style.left = '0';
document.body.appendChild(img);
var img2 = document.createElement('img');
img2.src = 'https://www.baidu.com/img/bd_logo1.png';
img2.style.width = '200px';
img2.style.height = '200px';
img2.style.position = 'absolute';
img2.style.top = '0';
img2.style.left = '100px';
img2.style.display = 'none';
document.body.appendChild(img2);
img.addEventListener('mouseover', function() {
  img2.style.display = 'block';
});
img.addEventListener('mouseout', function() {
  img2.style.display = 'none';
});
img.addEventListener('mousemove', function(e) {
  var x = e.clientX;
  var y = e.clientY;
  img2.style.top = y - 100 + 'px';
  img2.style.left = x + 'px';
});