淡入淡出焦点图效果类
这里是缓动焦点图链接：
JavaScript 缓动焦点图实现的几种写法 封装 + 函数式 + JQuery
焦点图
实现思路：
原生JS的类的调用方式：
var slider1 = new Slider({id:'focus_pic', /**包裹图片的UL的ID**/btnId:"focus_btn", //幻灯片按钮的ID,可以用来控制CSS显示//step:5, //透明度变化步长，默认为2autoTime:2000//自动播放间隔时间});
幻灯片的HTML书写方式：
<ul id="focus_pic"><li><a target="_blank" href="javascript:"><img src="/cnblogs_com/NNUF/379856/o_01.jpg"
width="530" height="180" alt=""></a></li><li><a target="_blank" href="javascript:"><img src="/cnblogs_com/NNUF/379856/o_02.jpg"
width="530" height="180" alt=""></a></li><li><a target="_blank" href="javascript:"><img src="/cnblogs_com/NNUF/379856/o_03.jpg"
width="530" height="180" alt=""></a></li><li><a target="_blank" href="javascript:"><img src="/cnblogs_com/NNUF/379856/o_04.jpg"
width="530" height="180" alt=""></a></li></ul>
幻灯片的原生JavaScript代码：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/><title>焦点图</title><style type="text/css">#focus_box {position: relative;margin: 0 auto;zoom: 1;width: 530px;height: 180px;overflow: hidden;}#focus_box ul {list-style: none;padding: 0;margin: 0;}#focus_btn {position: absolute;right: 5px;bottom: 5px;z-index: 2;}#focus_pic {position: absolute;}#focus_pic li {position: absolute;left: 0;}#focus_pic li img {border: none;float: left;}#focus_btn li {float: left;font-size: 12px;width: 25px;height: 25px;line-height: 25px;font-weight: bold;text-align: center;background: #fff;color: #000;margin-right: 2px;cursor: pointer;border-radius: 20px;}#focus_btn li.on {background: #f60;color: #fff;}#focus_box1 {position: relative;margin: 0 auto;overflow: hidden;zoom: 1;}#focus_box1 ul {list-style: none;padding: 0;margin: 0;}</style></head><body><div id="focus_box"><ul id="focus_pic"><li><a><img src="/cnblogs_com/NNUF/379856/o_01.jpg"></a></li><li><a><img src="/cnblogs_com/NNUF/379856/o_02.jpg"></a></li><li><a><img src="/cnblogs_com/NNUF/379856/o_03.jpg"></a></li><li><a><img src="/cnblogs_com/NNUF/379856/o_04.jpg"></a></li></ul></div><script type="text/javascript">(function () {//先设置两个简洁函数获取ID，设置透明度var $ = function () {var elements = new Array();for (var i = 0; i < arguments.length; i++) {var element = arguments[i];if (typeof element == 'string')element = document.getElementById(element);if (!element) continue;if (arguments.length == 1) return element;elements.push(element);}return elements;};var setOpacity = function (node, level) {node = $(node);if (document.all) {node.style.filter = 'alpha(opacity=' + level + ')';} else {node.style.opacity = level / 100;}};var getTag = function (child, parent) {return parent.getElementsByTagName(child);};var bindEvent = function (element, type, func) {if (element.addEventListener) {element.addEventListener(type, func, false); //false 表示冒泡} else if (element.attachEvent) {element.attachEvent('on' + type, func);} else {element['on' + type] = func;}};function Slider(options) {var id = options.id;var warper = this.warper = $(id);//获取包裹图片DOM(第一个UL的ID)var warpLis = this.warpLis = getTag("li", warper);//获取包裹下的LI子元素this.no = warpLis.length;//获取包裹LI元素的个数this.step = options.step || 2;this.autoTime = options.autoTime || 1000; //自动播放间隔时间this.btnId = options.btnId || "focus_btn"; //图片上面的数字按钮的IDthis.index = 1; // 开始变幻时的下一个INDEXthis.preIndex = 0;this.init();}Slider.prototype = {init:function () {this.makeBtn(this.no, this.btnId);this.autoPlay();},makeBtn:function (no, c) {//生成按钮 no表示个数 C表示UL的IDvar btnUl = this.btnUl = document.createElement("ul");btnUl.id = c;for (var i = 0; i < no; i++) {var li = document.createElement('li');if (i == 0) li.className = 'on';var text = document.createTextNode(i + 1);li.appendChild(text);setOpacity(li, 80);// 绑定鼠标事件，传递当前的INDEX和preIndexbindEvent(li, 'mouseover', function (obj, t) {return function () {obj.mouseOn.call(obj, t);}}(this, i));btnUl.appendChild(li);}this.warper.parentNode.appendChild(btnUl);//添加到父div下},autoPlay:function(){var that = this;// 执行播放clearTimeout(this.T1);this.T1 = setTimeout(function(){that.fadeIn(that.index)},that.autoTime);},fadeIn:function(index){var thisObj = this.warpLis[index];var thisOpacity = 0; //当前透明度从0渐入var that = this;// 底部按钮的同步,与当前的图层Z-index始终在上面var btnLi = getTag('li', this.btnUl);for (var i = 0, n = btnLi.length; i < n; i++) {btnLi[i].className = '';// 移除所有的Zindexthis.warpLis[i].style.zIndex = '';}//在改变INDEX之前先设置透明度为0setOpacity(this.warpLis[index],0);// 设置前一个图片的Zindexthis.warpLis[that.preIndex].style.zIndex = 1;// 设置当前图片的Zindexthis.warpLis[index].style.zIndex = 2;btnLi[index].className = 'on';//淡入动画if(that.T2)clearInterval(that.T2);this.T2 = setInterval(function(){setOpacity(thisObj,thisOpacity++); // 设置透明度渐入if(thisOpacity == 100){thisOpacity = 0;clearInterval(that.T2);that.T2 = null;that.preIndex = that.index ++;if(that.index == that.no)that.index = 0;that.autoPlay();}},10);},mouseOn:function(index){this.index = index;this.fadeIn(index);}};var slider1 = new Slider({id:'focus_pic', /**包裹图片的UL的ID**/btnId:"focus_btn", //幻灯片按钮的ID,可以用来控制CSS显示//step:5, //透明度变化步长，默认为2autoTime:2000//自动播放间隔时间});})();</script></body></html>
用Jquery 方法实现代码：
slider函数的参数解释：id-包裹UL的DIV的id，autoTime-自动播放时间，btn-为是否需要控制按钮，此参数不填即带控制按钮
调用方法：
slider("focus_pic", 3000);//层的ID与自动播放时间
slider("focus_pic", 3000,"noButton"); //幻灯片不带按钮
var slider = function (id, autoTime, btn) {var $div = $("#" + id), len = $("li", $div).length;var index = 1, timer, preIndex = 0;// 初始化$div.find("li").css("opacity", 0).eq(0).css("opacity", 1);// 生成按钮if (!btn) {var $dl = $("<dl id='J_flashBtn'></dl>");for (var i = 0; i < len; i++) {var $dt = $("<dt>" + (i + 1) + "</dt>");$dl.append($dt);}$div.append($dl);$dl.find("dt").css("opacity", 0.8).eq(0).addClass("on");// 按钮事件$dl.find("dt").hover(function () {clearInterval(timer);index = $(this).index();$(this).addClass("on").siblings().removeClass("on");auto(index);
preIndex = index;}, function () {timer = setInterval(function () {auto(index);preIndex = index++;if (index > len - 1) index = 0;}, autoTime);});}// 循环执行timer = setInterval(function () {auto(index);preIndex = index++;if (index > len - 1) index = 0;}, autoTime);// 主要动画function auto(index) {$div.find("li").eq(preIndex).css("z-index","0").stop(true, false).animate({opacity:0}, 800);$div.find("li").eq(index).css("z-index","1").stop(true, false).animate({opacity:1}, 800);if(!btn){$dl.find("dt").eq(index).addClass("on").siblings().removeClass("on");}}};
