妙味——拖拽+碰撞+重力

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>Document</title>
<style>
#div1{width: 100px;height: 100px;background: red;position: absolute;}
div{width: 3px;height: 3px;background: black;position: absolute;}
</style>
<script>
window.onload=function(){
    var oDiv=document.getElementById('div1');

    var lastX=0;
    var lastY=0;

    oDiv.onmousedown=function(ev){
        // alert(1);
        var oEvent=ev||event;
        var disX=oEvent.clientX-oDiv.offsetLeft;
        var disY=oEvent.clientY-oDiv.offsetTop;

        document.onmousemove=function(ev)
        {
            var oEvent=ev||event;

            var l=oEvent.clientX-disX;
            var t=oEvent.clientY-disY;

            oDiv.style.left=l+'px';
            oDiv.style.top=t+'px';

            iSpeedX=l-lastX;
            iSpeedY=t-lastY;

            lastX=l;
            lastY=t;

            document.title='x:'+iSpeedX+',y:'+iSpeedY;

        };

        document.onmouseup=function()
        {
            document.onmousemove=null;
            document.onmouseup=null;

            startMove();
        };

        clearInterval(timer);
    };
};

var timer=null;

var iSpeedX=0;
var iSpeedY=0;

function startMove()
{
    clearInterval(timer);

    timer=setInterval(function (){
        var oDiv=document.getElementById('div1');

        iSpeedY+=3;

        var l=oDiv.offsetLeft+iSpeedX;
        var t=oDiv.offsetTop+iSpeedY;

        if(t>=document.documentElement.clientHeight-oDiv.offsetHeight)
        {
            iSpeedY*=-0.8;
            iSpeedX*=0.8;
            t=document.documentElement.clientHeight-oDiv.offsetHeight;
        }
        else if(t<=0)
        {
            iSpeedY*=-1;
            iSpeedX*=0.8;
            t=0;
        }

        if(l>=document.documentElement.clientWidth-oDiv.offsetWidth)
        {
            iSpeedX*=-0.8;
            l=document.documentElement.clientWidth-oDiv.offsetWidth;
        }
        else if(l<=0)
        {
            iSpeedX*=-0.8;
            l=0;
        }

        if(Math.abs(iSpeedX)<1)
        {
            iSpeedX=0;
        }
        if(Math.abs(iSpeedY)<1)
        {
            iSpeedY=0;
        }

        if(iSpeedX==0 && iSpeedY==0 && t=document.documentElement.clientHeight-oDiv.offsetHeight)
        {
            clearInterval(timer);
        }
        else
        {
            oDiv.style.left=l+'px';
            oDiv.style.top=t+'px';    
        }
    },30);
};
</script>
</head>
<body>
    <div id="div1"></div>
</body>
</html>

 

posted @ 2013-12-28 23:31  白小虫  阅读(187)  评论(0编辑  收藏  举报