/*
power by: Tim Zhang
*/
//主函数
var s=function(){
var interv=4000; //切换间隔时间
var interv2=20; //切换速速
var opac1=80; //文字背景的透明度
var source="fade_focus" //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="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="b1";a.onmouseover=function(){this.className="b2"};a.onmouseout=function(){this.className="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="b1"};button.childNodes[n].className="b2";}
title.className="num_list";title.appendChild(span);alpha(title,opac1);id.className="d1";div.className="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();
}
//初始化
window.onload=s;