一样的代码，一样的逻辑，不一样的效果（选项卡和轮播图）

今天写了几个常用的前段demo，发现逻辑一样，而且实现了之前很难实现的效果。

1选项卡：

效果：

html：

 1 <div class="wrap">
 2             <div class="menus">
 3                 <ul>
 4                     <li class="active-item">item1</li>
 5                     <li>item2</li>
 6                     <li>item3</li>
 7                     <li>item4</li>
 8                 </ul>
 9             </div>
10             <hr />
11             <div class="tab_list">
12 
13                 <div class="box" style="opacity: 1;">
14                     1
15                 </div>
16 
17                 <div class="box item2">
18                     2
19                 </div>
20 
21                 <div class="box item3">
22                     3
23                 </div>
24 
25                 <div class="box item4">
26                     4
27                 </div>
28 
29             </div>
30         </div>

css：

 1 * {
 2                 padding: 0;
 3                 margin: 0;
 4                 /*border: 1px solid red;*/
 5             }
 6             
 7             .wrap {
 8                  500px;
 9                 height: 300px;
10             }
11             
12             .menus {
13                 overflow: hidden;
14             }
15             
16             .menus ul{
17                  100%;
18                 height: 30px;
19             }
20             .menus ul li {
21                 display: inline-block;
22                 float: left;
23                 height: 20px;
24                 padding: 5px 10px;
25                 font-size: 16px;
26                 cursor: pointer;
27             }
28             
29             hr{
30                 border: 2.5px solid #DFDFDF;
31                 margin-top: -5px;
32             }
33             
34             .active-item{
35                 color: cadetblue;
36                 border-bottom: 5px solid cadetblue;
37             }
38             
39             .tab_list{
40                  500px;
41                 height: 250px;
42                 margin-top: 10px;
43                 position: relative;
44                 border: 1px solid #DFDFDF;
45             }
46             
47             .box {
48                 position: absolute;
49                  500px;
50                 height: 250px;
51                 top: 0px;
52                 left: 0px;
53                 opacity: 0;
54                 transition: 1s;
55             }

js:

 1 var menu = document.getElementsByClassName('menus')[0];
 2         var item = menu.getElementsByTagName('li');
 3         var list = document.getElementsByClassName('tab_list')[0];
 4         var box = list.getElementsByClassName('box');
 5         var i = 0;
 6         var num = 0;
 7         var timer = null;
 8         
 9         for(i = 0; i < item.length; i++){
10             item[i].index = i;
11             item[i].onmouseover = function(){
12                 clearInterval(timer);
13                 num = this.index;
14                 tabChange(num);
15             }
16             item[i].onmouseout = function(){
17                 autoplay();
18             }
19         }
20         
21         function tabChange(num){
22             for(i = 0; i < item.length; i++){
23                 item[i].className = "";
24                 box[i].style.opacity = '0';
25             }
26             item[num].className = 'active-item';
27             box[num].style.opacity = '1';
28         }
29         
30         function autoplay() {
31             timer = setInterval(function() {
32                 //数值变化
33                 num++;
34                 if(num >= item.length) num = 0;
35                 //切换
36                 tabChange(num); //切换
37             }, 2000);
38         }
39         //开启自动播放
40         autoplay();

稍作改动，实现了轮播图效果

代码：

  1 <!DOCTYPE html>
  2 <html>
  3 
  4     <head>
  5         <meta charset="UTF-8">
  6         <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
  7         <title>轮播图</title>
  8         <style type="text/css">
  9             * {
 10                 padding: 0;
 11                 margin: 0;
 12                 /*border: 1px solid red;*/
 13             }
 14             
 15             .wrap {
 16                 width: 500px;
 17                 height: 300px;
 18             }
 19             
 20             .menus {
 21                 overflow: hidden;
 22             }
 23             
 24             .menus ul {
 25                 width: 100%;
 26                 height: 30px;
 27             }
 28             
 29             .menus ul li {
 30                 display: inline-block;
 31                 float: left;
 32                 width: 80px;
 33                 height: 80px;
 34                 border: 2px solid transparent;
 35                 padding: 0px;
 36                 font-size: 16px;
 37                 cursor: pointer;
 38                 opacity: 0.5;
 39             }
 40             .menus ul li img{
 41                 width: 100%;
 42                 height: 100%;
 43             }
 44             hr {
 45                 border: 2.5px solid #DFDFDF;
 46                 margin-top: -5px;
 47             }
 48             
 49             .active-item {
 50                 opacity: 1 !important;
 51             }
 52             
 53             .tab_list {
 54                 width: 500px;
 55                 height: 250px;
 56                 margin-top: 10px;
 57                 position: relative;
 58                 border: 1px solid #DFDFDF;
 59             }
 60             
 61             .box {
 62                 position: absolute;
 63                 width: 500px;
 64                 height: 250px;
 65                 top: 0px;
 66                 left: 0px;
 67                 opacity: 0;
 68                 transition: 1s;
 69             }
 70             
 71             .box img{
 72                 width: 100%;
 73                 height: 100%;
 74             }
 75         </style>
 76     </head>
 77 
 78     <body>
 79         <div class="wrap">
 80             <div class="tab_list">
 81 
 82                 <div class="box" style="opacity: 1;">
 83                     <img src="../img/timg (1).jpg"/>
 84                 </div>
 85 
 86                 <div class="box item2">
 87                     <img src="../img/timg (2).jpg"/>
 88                 </div>
 89 
 90                 <div class="box item3">
 91                     <img src="../img/timg (3).jpg"/>
 92                 </div>
 93 
 94                 <div class="box item4">
 95                     <img src="../img/timg (4).jpg"/>
 96                 </div>
 97 
 98             </div>
 99             <div class="menus">
100                 <ul>
101                     <li class="active-item"><img src="../img/timg (1).jpg"/></li>
102                     <li><img src="../img/timg (2).jpg"/></li>
103                     <li><img src="../img/timg (3).jpg"/></li>
104                     <li><img src="../img/timg (4).jpg"/></li>
105                 </ul>
106             </div>
107         </div>
108     </body>
109     <script type="text/javascript">
110         var menu = document.getElementsByClassName('menus')[0];
111         var item = menu.getElementsByTagName('li');
112         var list = document.getElementsByClassName('tab_list')[0];
113         var box = list.getElementsByClassName('box');
114         var i = 0;
115         var num = 0;
116         var timer = null;
117 
118         for(i = 0; i < item.length; i++) {
119             item[i].index = i;
120             item[i].onmouseover = function() {
121                 clearInterval(timer);
122                 num = this.index;
123                 tabChange(num);
124             }
125             item[i].onmouseout = function(){
126                 autoplay();
127             }
128         }
129 
130         function tabChange(num) {
131             for(i = 0; i < item.length; i++) {
132                 item[i].className = "";
133                 box[i].style.opacity = '0';
134             }
135             item[num].className = 'active-item';
136             box[num].style.opacity = '1';
137         }
138 
139         //自动播放 = 数值变化 + 切换
140         function autoplay() {
141             timer = setInterval(function() {
142                 //数值变化
143                 num++;
144                 if(num >= item.length) num = 0;
145                 //切换
146                 tabChange(num); //切换
147             }, 2000);
148         }
149         //开启自动播放
150         autoplay();
151     </script>
152 </html>