var brOK=false;			//可行性检测
var mie=false;			//是否为IE
var aver=parseInt(navigator.appVersion.substring(0,1));
var aname=navigator.appName;
//var vmin=2;
//var vmax=5;
var vmin=1;
var vmax=2;
var vr=0.02;
var timer1;
var movediv;

var winDocStr="window.document";

function getWinDoc(){
	return eval(winDocStr);
}
function getWinObjStr(){
	return winDocStr+".all";
}
function getWinObj(){
	return getWinDoc().all;
}

function checkbrOK(){
	if(aname.indexOf("Internet Explorer")!=-1){
		if(aver>=4){
			brOK=navigator.javaEnabled();
		}
		mie=true;
	}
	if(aname.indexOf("Netscape")!=-1){
		if(aver>=4){
			brOK=navigator.javaEnabled();
		}
	}
}

function Chip(chipname,width,height){
	this.named=chipname;
	this.vx=vmin+vmax*Math.random();
	this.vy=vmin+vmax*Math.random();
	this.w=width;
	this.h=height;
	this.xx=0;
	this.yy=60;
	this.timer1=null;
}

function movechip(chipname){
	if(brOK){
		eval("chip="+chipname);
		if(!mie){
			pageX=getWinDoc().pageXOffset;
			pageW=getWinDoc().innerWidth;
			pageY=getWinDoc().pageYOffset;
			pageH=getWinDoc().innerHeight;
		}else{
			pageX=getWinDoc().body.scrollLeft;
			pageW=getWinDoc().body.offsetWidth-22;
			pageY=getWinDoc().body.scrollTop;
			pageH=getWinDoc().body.offsetHeight-25;
		} 
		chip.xx=chip.xx+chip.vx;
		chip.yy=chip.yy+chip.vy;

		chip.vx+=vr*(Math.random()-0.5);
		chip.vy+=vr*(Math.random()-0.5);
		if(chip.vx>(vmax+vmin))  chip.vx=(vmax+vmin)*2-chip.vx;
		if(chip.vx<(-vmax-vmin)) chip.vx=(-vmax-vmin)*2-chip.vx;
		if(chip.vy>(vmax+vmin))  chip.vy=(vmax+vmin)*2-chip.vy;
		if(chip.vy<(-vmax-vmin)) chip.vy=(-vmax-vmin)*2-chip.vy;

		if(chip.xx<=pageX){
			chip.xx=pageX;
			chip.vx=vmin+vmax*Math.random();
		}
		if(chip.xx>=pageX+pageW-chip.w){
			chip.xx=pageX+pageW-chip.w;
			chip.vx=-vmin-vmax*Math.random();
		}
		if(chip.yy<=pageY){
			chip.yy=pageY;
			chip.vy=vmin+vmax*Math.random();
		}
		if(chip.yy>=pageY+pageH-chip.h){
			chip.yy=pageY+pageH-chip.h;
			chip.vy=-vmin-vmax*Math.random();
		}

		if(!mie){
			eval('document.'+chip.named+'.top ='+chip.yy);
			eval('document.'+chip.named+'.left='+chip.xx);
		}else{
			eval(getWinObjStr()+'.'+chip.named+'.style.pixelLeft='+chip.xx);
			eval(getWinObjStr()+'.'+chip.named+'.style.pixelTop ='+chip.yy); 
		}
		chip.timer1=setTimeout("movechip('"+chip.named+"')",150);
	}
}

function hide(chipname){
	if(brOK){
		eval("chip="+chipname);
		if(!mie){
			eval('document.'+chip.named+'.visibility ='+"'hide'");
		}else{
			eval(getWinObjStr()+'.'+chip.named+'.style.visibility ='+"'hidden'");
		}
	}
}

function stopme(chipname){
	if(brOK){
		eval("chip="+chipname);
		if(chip.timer1!=null){
			clearTimeout(chip.timer1)
		}
	}
}
function pagestart(){
	mg_dis(getWinObj().movediv);
	checkbrOK();
	movediv=new Chip("movediv",120,70);
	if(brOK){
		movechip("movediv");
	}
}

function mg_dis(k){
	if (k.style.display=="none"){
		k.style.display="";
	}else{
		k.style.display="none";
	}
}
function goFly(){
	setTimeout("pagestart();", (1000));
}