//引入script的时候可以接受如下参数
//<script type="text/javascript" src="float.js?id=id&stepx=stepx&stepy=stepy&delay=delay"></script>
//id  飘窗元素id
//stepx  每经过delay时间，水平方向上移动stepx个像素
//stepy  每经过delay时间，竖直方向上移动stepy个像素
//delay  每次移动的时间间隔，以ms为单位

var id, stepX, stepY, delay, left = 0, top1 = 0, objWidth, objHeight, bodyWidth, bodyHeight, directionX = "right", directionY = "down", floatObj;
//解析js文件后面的参数
var getArgs = (function(){
var sc=document.getElementsByTagName("script");
var paramsArr=sc[sc.length-1].src.split('?')[1].split('&');
var args={},argsStr=[],param,t,name,value;
for(var ii=0,len=paramsArr.length;ii<len;ii++){
param=paramsArr[ii].split('=');
name=param[0],value=param[1];
if(typeof args[name]=="undefined"){ //参数尚不存在
args[name]=value;
}else if(typeof args[name]=="string"){ //参数已经存在则保存为数组
args[name]=[args[name]]
args[name].push(value);
}else{ //已经是数组的
args[name].push(value);
}
}
return function(){return args;} //以json格式返回获取的所有参数
})();

var move = function() {
	//判断移动方向
	if(directionX == "right") {
		if((left + objWidth + stepX) > bodyWidth) {
			directionX = "left";
		}
	} else {
		if((left - stepX) < 0) {
			directionX = "right";
		}
	}
	
	if(directionY == "down") {
		if((top1 + objHeight + stepY) > bodyHeight) {
			directionY = "up";
		}
	} else {
		if((top1 - stepY) < 0) {
			directionY = "down";
		}
	}
	
	//移动
	if(directionX == "right") {
		left += stepX;
	} else {
		left -= stepX;
	}
	if(directionY == "down") {
		top1 += stepY;
	} else {
		top1 -= stepY;
	}
	floatObj.style.left = left + "px";
	floatObj.style.top = top1 + "px";
};

var start = function() {
	interval = setInterval('move()', delay);
};

//获取参数
var params = getArgs();
id = params.id;
stepX = parseFloat(params.stepx);
stepY = parseFloat(params.stepy);
delay = parseFloat(params.delay);

window.addEventListener("load", function() {
	floatObj = document.getElementById(id);
	objWidth = parseFloat(floatObj.style.width);
	objHeight = parseFloat(floatObj.style.height);
	floatObj.style.position = "fixed";
	floatObj.style.zIndex = 99999999;
	floatObj.style.left = left + "px";
	floatObj.style.top = top1 + "px";
	
	bodyWidth = parseFloat(document.body.clientWidth);
	bodyHeight = parseFloat(document.body.clientHeight);

	start();
	
	floatObj.addEventListener("mouseover", function(){clearInterval(interval)});
	floatObj.addEventListener("mouseout", function(){interval=setInterval('move()', delay)});
});