简单的碰撞运动


需要的js

//碰撞运动
//对运动的方向以及临界值的处理
function bumpMove(obj) {
    clearInterval(obj.timer);
    var speedX = 10;
    var speedY = 10;
    timer = setInterval(function() {
        var L = obj.offsetLeft + speedX;
        var T = obj.offsetTop + speedY;

        if(T > document.documentElement.clientHeight - obj.offsetHeight) {
            T = document.documentElement.clientHeight - obj.offsetHeight;
            speedY *= -1;
        } else if(T < 0) {
            T = 0;
            speedY *= -1;
        }
        if(L > document.documentElement.clientWidth - obj.offsetWidth) {
            L = document.documentElement.clientWidth - obj.offsetWidth;
            speedX *= -1;
        } else if(L < 0) {
            L = 0;
            speedX *= -1;
        }

        obj.style.left = L + 'px';
        obj.style.top = T + 'px';
    }, 30);

}



<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
        <link rel="stylesheet" type="text/css" href="../css/public.css"/>
        <style type="text/css">
            #div1{width: 100px;height: 100px;background: red;position: absolute;}
        </style>
        <script type="text/javascript" src="../js/rainbow.js"></script>
        <script type="text/javascript">
            window.onload=function(){
                var oDiv=document.getElementById("div1");
                bumpMove(oDiv);
            }
        </script>
    </head>
    <body>
        <div id="div1"></div>
    </body>
</html>