//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)});
});