/*
by: /
*/
//主函数
var s = function() {
    var interv = 3500; //切换时间
    var interv2 = 10; //切换速速
    var opac1 = 80; //文字背景的透明度
    var source = "fade_focus" //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;