基于javascript实现图片滑动效果

<div class="container">     <h1>Parallax Slider</h1>     <div class="wrap">       <div class="bg-img">         <div id="bg_1" class="bg bg-1" style="left: 0px;"></div>         <div id="bg_2" class="bg bg-2" style="left: 0px;"></div>         <div id="bg_3" class="bg bg-3" style="left: 0px;"></div>       </div>       <div id="wrap_panel" class="wrap-panel" style="left: 0px;">         <div class="panel panel-1">           <img id="img_1" src="images/1.jpg">         </div>         <div class="panel panel-2">           <img src="images/2.jpg">         </div>         <div class="panel panel-3">           <img src="images/3.jpg">         </div>         <div class="panel panel-4">           <img src="images/4.jpg">         </div>         <div class="panel panel-5">           <img src="images/5.jpg">         </div>         <div class="panel panel-6">           <img src="images/6.jpg">         </div>       </div>       <div class="navigation-button">         <span id="perv_btn" class="perv-button"></span>         <span id="next_btn" class="next-button"></span>       </div>       <div id="show_small" class="show-small">         <ul>           <li><img src="images/thumbs/1.jpg"></li>           <li><img src="images/thumbs/2.jpg"></li>           <li><img src="images/thumbs/3.jpg"></li>           <li><img src="images/thumbs/4.jpg"></li>           <li><img src="images/thumbs/5.jpg"></li>           <li><img src="images/thumbs/6.jpg"></li>         </ul>       </div>     </div>   </div> 

* { margin: 0; padding: 0; }   html, body, .container { width: 100%; height: 100%; font-family: 'Microsoft Yahei'; }   .container { background-color: #222; overflow-x: hidden; }   .container h1 { font-size: 50px; color: #ccc; text-align: center; font-weight: bolder; height: 120px; line-height: 120px; }   .wrap { position: relative; width: 600%; height: 400px; border-top: 10px solid #333; border-bottom: 10px solid #333; margin-top: 20px; }   .bg { position: absolute; width: 100%; height: 100%; left: 0; top: 0; -webkit-transition: all 1s;-moz-transition: all 1s;-ms-transition: all 1s;-o-transition: all 1s;transition: all 1s; }   .bg-1 { background: url(images/bg1.png); }   .bg-2 { background: url(images/bg2.png); }   .bg-3 { background: url(images/bg3.png); }   .wrap-panel { position: absolute; width: 100%; height: 100%; -webkit-transition: all 1s; -moz-transition: all 1s; -ms-transition: all 1s; -o-transition: all 1s; transition: all 1s; }   .panel { width: 16.66%; height: 100%; float: left; }   .panel img { display: block; margin: 0 auto; margin-top: 35px; border-radius: 10px; border: 10px solid rgba(143, 143, 143, 0.6); }   .navigation-button span:hover { opacity: 0.8 }   .perv-button, .next-button { position: absolute; width: 30px; height: 60px; background-color: #344133; border-radius: 10px; cursor: pointer; opacity: 0.4; }   .perv-button { background: #000 url(images/prev.png) center center no-repeat; }   .next-button { background: #000 url(images/next.png) center center no-repeat; }   .show-small { position: absolute; width: 680px; bottom: 20px; }   .show-small ul { list-style: none; }   .show-small ul li { float: left; margin: 0 10px; border: 5px solid #fff; opacity: 0.7; cursor: pointer;-webkit-transition: all .3s; -moz-transition: all .3s; -ms-transition: all .3s;-o-transition: all .3s; transition: all .3s; }   .show-small ul li:hover { margin-top: -15px; } 

window.onload = function() {       // 得到元素       var getDOM = function (id){         return typeof id==="string"?document.getElementById(id):id;       }        // 得到对象       var img = getDOM('img_1');       var prev = getDOM("perv_btn");       var next = getDOM("next_btn");       var wrap_panel = getDOM('wrap_panel');       var bg_1 = getDOM("bg_1");       var bg_2 = getDOM("bg_2");       var bg_3 = getDOM("bg_3");       var show_small = getDOM("show_small");       var list = show_small.getElementsByTagName("li");       var wwidth;         // 为元素绑定事件       var addEvent = function(id,event,fn) {        var el = getDOM(id) || document;        if(el.addEventListener){         el.addEventListener(event,fn,false);        }else if(el.attachEvent){         el.attachEvent('on' + event,fn);        }       }       function init() {                  // 对按钮进行定位         // 向前按钮的左边距离=图片的左距离+边框         prev.style.left = img.offsetLeft + 10 + 'px';         // 向前按钮的上边距离=图片的上距离+图片高度的一半-按钮高度的一半         prev.style.top = img.offsetTop + img.clientHeight/2 - prev.clientHeight/2 + 'px';         next.style.left = img.offsetLeft + img.clientWidth + 10 - next.clientWidth + 'px';         next.style.top =prev.style.top;          // 对小图片的容器进行定位         wwidth = document.documentElement.clientWidth || document.body.clientWidth;         show_small.style.left = (wwidth - show_small.clientWidth)/2 + 'px';       }        // 小图片的处理       function small_img() {         // 对图片进行旋转处理         for (var i = 0;i< list.length; i++) {           // 旋转方向           var direction = Math.pow(-1,parseInt(Math.random()*10));           list[i].style = "transform:rotate(" + (Math.random()*20*direction) + "deg)";         }         list[0].style.opacity = 1;       }        function only_one(el,num) {         for (var i = 0; i < el.length; i++) {           el[i].style.opacity = 0.7;         }         // console.log(num);         el[num].style.opacity = 1;       }        // 浏览器缩放时       window.onresize = function() {         init();       }            // 执行函数       init();       small_img();       addEvent(prev,'click',function() {         // 改变wrap-panel的left         var oldPos = parseInt(wrap_panel.style.left);                  if(oldPos == 0) {              // 背景平移 图片容器平移           bg_1.style.left=bg_2.style.left=bg_3.style.left=wrap_panel.style.left = -wwidth*(list.length-1) +'px';            // 更改对应小图片透明度           only_one(list,list.length-1);         } else {            // 背景平移 图片容器平移           wrap_panel.style.left = (oldPos + wwidth) +'px';           bg_1.style.left= (oldPos + wwidth - parseInt(-(oldPos/wwidth + 1))*100) +'px';           bg_2.style.left= (oldPos + wwidth - parseInt(-(oldPos/wwidth + 1))*300) +'px';           bg_3.style.left= (oldPos + wwidth - parseInt(-(oldPos/wwidth + 1))*500) +'px';            // 更改对应小图片透明度           only_one(list,parseInt(-(oldPos/wwidth + 1)));         }       });       addEvent(next,'click',function() {         // 改变wrap-panel的left         var oldPos = parseInt(wrap_panel.style.left);                  if(oldPos == -wwidth*(list.length-1)) {               // 背景平移 图片容器平移           bg_1.style.left=bg_2.style.left=bg_3.style.left=wrap_panel.style.left = '0px';            // 更改对应小图片透明度           only_one(list,0);         } else {           // 背景平移 图片容器平移           wrap_panel.style.left = (oldPos - wwidth) +'px';           bg_1.style.left= (oldPos - wwidth + parseInt(-(oldPos/wwidth + 1))*100) +'px';           bg_2.style.left= (oldPos - wwidth + parseInt(-(oldPos/wwidth + 1))*300) +'px';           bg_3.style.left= (oldPos - wwidth + parseInt(-(oldPos/wwidth + 1))*500) +'px';            // 更改对应小图片透明度           only_one(list,parseInt(-(oldPos/wwidth - 1)));         }       });     }