var imgs = new Array();
for(var n = 1; n <= 2; n++) imgs[n] = new Image();
imgs[1].src = "../images/index1.jpg";
imgs[2].src = "../images/index2.jpg";

var tits = new Array();
var imgwidth = 680;//图片宽度
var imgheight = 294;//图片宽度
var str= "<div><img id='dimg' src='" + imgs[1].src + "' border='0' width='" + imgwidth + "' height='"+imgheight+"' style='filter:Alpha(opacity=100)' onmouseover='Pause(true)' onmouseout='Pause(false)'></div>";
document.write(str);

var oi = document.getElementById("dimg");
var pause = false;
var curid = 1;
var lastid = 1;
var sw = 1;
var opacity = 150;
var speed = 5;
var delay = (document.all)?700:1000;

function SetAlpha(){
	if(document.all){
		if(oi.filters && oi.filters.Alpha) oi.filters.Alpha.opacity = opacity;
	}else{
		oi.style.MozOpacity = ((opacity >= 100)? 99:opacity) / 100;
	}
}

function ImgSwitch(id, p){
	if(p){
		pause = true;
		opacity =150;
		//SetAlpha();
	}
	oi.src = imgs[id].src;
	curid = lastid = id;
}

function ScrollImg(){
	if(pause && opacity >= 100) return;
	if(sw == 0){
		opacity += 2;
		if(opacity > delay){
			opacity = 100; sw = 1; 
		}
	}
	if(sw == 1){
		opacity -= 3;
		if(opacity < 10){ 
			opacity = 10; sw = 3; 
		}
	}
	//SetAlpha();
	if(sw != 3) return;
	sw = 0;
	curid++;
	//修改点2：这里的4也是个数
	if(curid > 2) curid = 1;
	ImgSwitch(curid, false);
}

function Pause(s){
	pause = s;
}


//第一次切换的时间设定
function StartScroll(){
	setInterval(ScrollImg, speed);
}


function CheckLoad(){
	if (imgs[1].complete == true && imgs[2].complete == true) {
		clearInterval(checkid);
		setTimeout(StartScroll, 8000);
	}	
}

var checkid = setInterval(CheckLoad, 1000);