// JavaScript Documentvar 
           s = function() {
            var interv = 5500;
            //切换间隔时间
            var interv2 = 20;
            //切换速速
            var opac1 = 50;
            //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 flash_button = document.createElement("div");
            flash_button.className = "flash_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 = "flash_button1";
                a.onmouseover = function() {
                    this.className = "flash_button2"
                };
                a.onmouseout = function() {
                    this.className = "flash_button1";
                    sc(j)
                };
                flash_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++) {
                    flash_button.childNodes[i].className = "flash_button1"
                };
                flash_button.childNodes[n].className = "flash_button2";
            }
            title.className = "num_list";
            title.appendChild(span);
            alpha(title, opac1);
            id.className = "flashchang1";
            div.className = "flashchange2";
            id.appendChild(div);
            id.appendChild(title);
            id.appendChild(flash_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;