var slide=function(sourceid,intervtime,btnnext){
    var interv=intervtime; //切换间隔时间
    var interv2=10; //切换速速
    var opac1=1; //文字背景的透明度
    if(btnnext)opac1=50;
    var btncontr=true
    var source=sourceid //焦点轮换图片容器的id名称
    var act="start"
    //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);
    }
    //添加Next按钮
    if(btnnext){
        var a=document.createElement("a");
        a.innerHTML='Next';
        a.onclick=function(){
            clearTimeout(timer);
            clearTimeout(timer2);
            clearTimeout(timer3);
            if(j+1 >= li.length)
                j=0;
            else
                j=j+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);
    }
    //添加Stop/Start按钮
    if(btncontr){
        var a=document.createElement("a");
        a.innerHTML='Stop';
        a.onclick=function(){
            if(act=="stop"){
                this.innerHTML="Stop"
                act="start"
                if(j+1 >= li.length) j=0;
                else j=j+1;
                scton=0;
                t=63;
                opac=0;
                fadeon()
            }else{
                clearTimeout(timer);
                clearTimeout(timer2);
                clearTimeout(timer3);
                this.innerHTML="Start"
                act="stop"
            }
        };
        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{
            if(act=="start") 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();
}