CSS code:
 1 .container{
 2   margin: 20px auto;
 3   padding:0 15px;
 4   width: 50%;
 5   height:300px;
 6   box-sizing: border-box;
 7 }
 8 .text-container{
 9   display: inline-block;
10   float:left;
11   width: 15%;
12   height: 32px;
13   line-height: 32px;
14   box-sizing: border-box;
15 }
16 .selectContainer{
17   width: 70%;
18   height:200px;
19   float:left;
20   position: relative;
21   padding:0;
22   margin:0;
23   box-sizing: border-box;
24 }
25 .selectedContent{
26   width:85%;
27   height: 25px;
28   float:left;
29 }
30 .dropDown-toggle{
31   width:14%;
32   height:31px;
33   line-height: 31px;
34   text-align: center;
35   border: 1px solid silver;
36   border-left:none;
37   float:left;
38   padding:0;
39   margin:0;
40   box-sizing: border-box;
41   cursor: pointer;
42 }
43 .dropDown-menu{
44   margin:0;
45   padding:0 15px 10px;
46   width:100%;
47   border:1px solid silver;
48   border-top: none;
49   box-sizing: border-box;
50   list-style: none;
51   position: absolute;
52   top:31px;
53   right:0;
54 }
55 .items{
56   margin-top:8px;
57   padding: 2px;
58   cursor: pointer;
59 }
60 .items:hover{
61   background: #ddd;
62 }
63 .dsn{
64   display: none;
65 } 

Html code:
 1 <div class="container">
 2     <span class="text-container">最爱的水果：</span>
 3     <div class="singleSelect selectContainer">
 4         <input type="text" class="selectedContent">
 5         <div class="dropDown-toggle">选择</div>
 6         <ul class="dropDown-menu dsn">
 7             <li class="items">苹果</li>
 8             <li class="items">梨</li>
 9             <li class="items">橘子</li>
10         </ul>
11     </div>
12 </div>

JavaScript code: 
 1 $(‘.items‘).on(‘click‘, function(){
 2     if($(this).parents(‘.selectContainer‘).hasClass(‘singleSelect‘)){
 3         $(this).parents(‘.selectContainer‘).find(‘.selectedContent‘).val($(this).text());
 4         $(this).parent().addClass(‘dsn‘);
 5     }
 6 });
 7 $(‘.dropDown-toggle‘).on(‘click‘, function(){
 8     $(this).next().toggleClass(‘dsn‘);
 9 });