仿京东放大镜效果，请教各位大牛js可以用backgroundPositionX 和 Y 吗，效果和img移动一样

Question

```javascript
<script>
            window.addEventListener('load', function() {
                var mask = document.querySelector('.mask');
            var box = document.querySelector('.box');
            var big = document.querySelector('.big');
            box.addEventListener('mouseover', function(e) {
                mask.style.display = 'block';
                big.style.display = 'block';
            })
            box.addEventListener('mouseout', function() {
                mask.style.display = 'none';
                big.style.display = 'none';
            })
            box.addEventListener('mousemove', function(e) {
                var mouse_x = e.pageX - box.offsetLeft;
                var mouse_y = e.pageY - box.offsetTop;
                var x = mouse_x - mask.offsetWidth*0.5;
                var y = mouse_y - mask.offsetHeight*0.5;
                var cha = box.offsetWidth - mask.offsetWidth;
                if (x <= 0) {
                    x = 0;
                } else if (x >= cha) {
                    x = cha;
                }
                if (y <= 0) {
                    y = 0;
                } else if (y >= cha) {
                    y = cha;
                }
                mask.style.left = x+'px';
                mask.style.top = y+'px';
                var big_x = (mask.offsetWidth/box.offsetWidth)*(big.offsetWidth/100);
                big.style.backgroundPositionX = -big_x*x + 'px' ;
                big.style.backgroundPositionY = -big_x*y + 'px';
            })
            })
        </script>

```

Answer 1

可以啊，用backgroundPositionX 和 backgroundPositionY 就是设置背景图片的位置，你具体要问什么？