原生JS实现各种运动之缓冲运动

<!DOCTYPE html>
<html>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>原生JS实现各种运动之缓冲运动</title>
    <style>
        #div1 {
            width: 100px;
            height: 100px;
            position: absolute;
            background: red;
            left: 0;
            top: 50px;
        }
    </style>

    <script type="text/javascript">
        var timer = null;

        function startMove(iTarget) {

            var oDiv = document.getElementById('div1');

            clearInterval(timer);

            timer = setInterval(function () {

                var iSpeed = (iTarget - oDiv.offsetLeft) / 8;
                iSpeed = iSpeed > 0 ? Math.ceil(iSpeed) : Math.floor(iSpeed);

                //是否到达终点
                if (oDiv.offsetLeft == iTarget) {
                    // 到达终点
                    clearInterval(timer);

                } else {
                    // 到达之前
                    oDiv.style.left = oDiv.offsetLeft + iSpeed + 'px';
                }
                // 以标题的形式打印出来
                // document.title=oDiv.offsetLeft+',speed='+iSpeed;
            }, 30);
        }

    </script>
</head>

<body>
    <input type="button" value="开始运动" onclick="startMove(300)" />
    <div id="div1"></div>
</body>

</html>