跟随鼠标移动的js代码
<!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">
<head>
<title>跟随鼠标移动的流星</title>
<meta http-equiv="content-type" content="text/html;charset=gb2312">
<style type="text/css">
html{
overflow:hidden;
}
body{
position:absolute;
height:100%;
width:100%;
margin:0;
padding:0;
}
#screen{
background:#000;
position:absolute;
width:100%;
height:100%;
}
#screen span{
background:#fff;
font-size:0;
overflow:hidden;
width:2px;
height:2px;
}
</style>
<script type="text/javascript">
var Follow = function () {
var $ = function (i) {return document.getElementById(i)},
addEvent = function (o, e, f) {o.addEventListener ? o.addEventListener(e, f, false) : o.attachEvent('on'+e, function(){f.call(o)})},
OBJ = [], sp, rs, N = 0, m;
var init = function (id, config) {
this.config = config || {};
this.obj = $(id);
sp = this.config.speed || 4;
rs = this.config.animR || 1;
m = {x: $(id).offsetWidth * .5, y: $(id).offsetHeight * .5};
this.setXY();
this.start();
}
init.prototype = {
setXY : function () {
var _this = this;
addEvent(this.obj, 'mousemove', function (e) {
e = e || window.event;
m.x = e.clientX;
m.y = e.clientY;
})
},
start : function () {
var k = 180 / Math.PI, OO, o, _this = this, fn = this.config.fn;
OBJ[N++] = OO = new CObj(null, 0, 0);
for(var i=0;i<360;i+=20){
var O = OO;
for(var j=10; j<35; j+=1){
var x = fn(i, j).x,
y = fn(i, j).y;
OBJ[N++] = o = new CObj(O , x, y);
O = o;
}
}
setInterval(function() {
for (var i = 0; i < N; i++) OBJ[i].run();
}, 16);
}
}
var CObj = function (p, cx, cy) {
var obj = document.createElement("span");
this.css = obj.style;
this.css.position = "absolute";
this.css.left = "-1000px";
this.css.zIndex = 1000 - N;
document.getElementById("screen").appendChild(obj);
this.ddx = 0;
this.ddy = 0;
this.PX = 0;
this.PY = 0;
this.x = 0;
this.y = 0;
this.x0 = 0;
this.y0 = 0;
this.cx = cx;
this.cy = cy;
this.parent = p;
}
CObj.prototype.run = function () {
if (!this.parent) {
this.x0 = m.x;
this.y0 = m.y;
} else {
this.x0 = this.parent.x;
this.y0 = this.parent.y;
}
this.x = this.PX += (this.ddx += ((this.x0 - this.PX - this.ddx) + this.cx) / rs) / sp;
this.y = this.PY += (this.ddy += ((this.y0 - this.PY - this.ddy) + this.cy) / rs) / sp;
this.css.left = Math.round(this.x) + 'px';
this.css.top = Math.round(this.y) + 'px';
}
return init;
}();
</script>
</head>
<body>
<div id="screen"></div>
<script type="text/javascript">
new Follow('screen', {
speed: 4,
animR : 2,
fn : function (i, j) {
return {
x : j/4*Math.cos(i),
y : j/4*Math.sin(i)
}
}
})
</script>
</body>
</html>
