JS——鼠标跟随

注意事项：
1、pageX、pageY的兼容问题
2、使目标移动鼠标中间位置还必须减去盒子宽度的一半
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

    <style>

        div {

            width: 100px;

            height: 100px;

            background-color: #ccc;

            position: absolute;

        }

    </style>

</head>

<body>

<div></div>

<script>

    var divEle = document.getElementsByTagName("div")[0];

    var timer = null;

    document.onclick = function (ev) {

        ev = ev || window.event;

        console.log(ev);

        var pageX = ev.pageX || scroll().left + ev.clientX;

        var pageY = ev.pageY || scroll().top + ev.clientY;

        animateX(divEle, pageX - 50, pageY - 50);

    }

    function animateX(ele, targetX, targetY) {

        clearInterval(timer);

        timer = setInterval(function () {

            var stepX = (targetX - ele.offsetLeft) / 10;

            stepX = stepX > 0 ? Math.ceil(stepX) : Math.floor(stepX);

            ele.style.left = ele.offsetLeft + stepX + "px";

            console.log(1);

            var stepY = (targetY - ele.offsetTop) / 10;

            stepY = stepY > 0 ? Math.ceil(stepY) : Math.floor(stepY);

            ele.style.top = ele.offsetTop + stepY + "px";

            if (Math.abs(targetX - ele.offsetLeft) <= Math.abs(stepX) && Math.abs(targetY - ele.offsetTop) <= Math.abs(stepY)) {

                ele.style.left = targetX + "px";

                ele.style.top = targetY + "px";

                clearInterval(timer);

            }

        }, 15);

    }

    function scroll() {

        return {

            "top": window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop,

            "left": window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft

        };

    }

</script>

</body>

</html>