// JavaScript Document
var focuspics = function(){
	var interv = 5000; //切换间隔时间
	var interv2 = 1; //切换速速
	var opac1 = 60; //文字背景的透明度
	var source = "focuspics" //焦点轮换图片容器的id名称
	//获取对象
	function getTag(tag,obj){
		if(obj == null){
			return document.getElementsByTagName(tag);
		}else{
			return obj.getElementsByTagName(tag);
		}
	};
	function getid(id){
		return document.getElementById(id);
	};
	var opac = 0,j = 0,t = 63,num,scton = 0,timer,timer2,timer3;
	var id = getid(source);
	id.removeChild(getTag("div",id)[0]);
	var li = getTag("li",id);
	var div = document.createElement("div");
	var title = document.createElement("div");
	var span = document.createElement("span");
	var button = document.createElement("div");
	button.className = "focuspics_button";
	for(var i = 0;i<li.length;i++){
		var a = document.createElement("a");
		a.innerHTML = i+1;
		a.onclick = function(){
			clearTimeout(timer);
			clearTimeout(timer2);
			clearTimeout(timer3);
			j = parseInt(this.innerHTML)-1;
			scton = 0;
			t = 63;
			opac = 0;
			fadeon();
		};
		a.className = "focuspics_b1";
		a.onmouseover = function(){
			this.className = "focuspics_b2";
		};
		a.onmouseout=function(){
			this.className = "focuspics_b1";
			sc(j);
		};
		button.appendChild(a);
	};
	//控制图层透明度
	function alpha(obj,n){
		if(document.all){
			obj.style.filter = "alpha(opacity="+n+")";
		}else{
			obj.style.opacity=(n/100);
		}
	};
	//控制焦点按钮
	function sc(n){
		for(var i = 0;i<li.length;i++){
			button.childNodes[i].className = "focuspics_b1"
		};
		button.childNodes[n].className = "focuspics_b2";
	}
	title.className = "focuspics_list";
	title.appendChild(span);
	alpha(title,opac1);
	id.className = "focuspics_d1";
	div.className = "focuspics_d2";
	id.appendChild(div);
	id.appendChild(title);
	id.appendChild(button);
	//渐显
	var fadeon = function(){
		opac+=5;
		div.innerHTML = li[j].innerHTML;
		span.innerHTML = getTag("img",li[j])[0].alt;
		alpha(div,opac);
		if(scton==0){
			sc(j);
			num=-2;
			scrolltxt();
			scton = 1;
		};
		if(opac<100){
			timer = setTimeout(fadeon,interv2);
		}else{
			timer2 = setTimeout(fadeout,interv);
			};
		}
	//渐隐
	var fadeout = function(){
		opac-=5;
		div.innerHTML = li[j].innerHTML;
		alpha(div,opac);
		if(scton == 0){
			num = 2;
			scrolltxt();
			scton = 1;
		};
		if(opac>0){
			timer = setTimeout(fadeout,interv2);
		}else{
			if(j<li.length-1){
				j++;
			}else{
				j = 0;
			};
			fadeon();
		};
	}
	//滚动文字
	var scrolltxt = function(){
		t+=num;span.style.marginTop=t+"px";
		if(num<0&&t>3){
			timer3 = setTimeout(scrolltxt,interv2)
		}else if(num>0&&t<62){
			timer3 = setTimeout(scrolltxt,interv2);
		}else{
			scton = 0;
		};
	};
	fadeon();
};