container{
   margin: 20px auto;
   padding:0 15px;
   width: 50%; 
   height:300px;
   box-sizing: border-box;  
  }
  .text-container{
   display: inline-block;
   float:left;
   width: 15%;
   height: 32px;
   line-height: 32px;
   box-sizing: border-box;
  }
  .selectContainer{
   width: 70%;
   height:200px;
   float:left;
   position: relative;
   padding:0;
   margin:0;
   box-sizing: border-box;
  }
  .selectedContent{
   width:85%;
   height: 25px;
   float:left;   
  }
  .dropDown-toggle{
   width:14%;
   height:31px;
   line-height: 31px;
   text-align: center;
   border: 1px solid silver;
   border-left:none;
   float:left;
   padding:0;
   margin:0;
   box-sizing: border-box;
   cursor: pointer;
  }
  .dropDown-menu{
   margin:0;
   padding:0 15px 10px;
   width:100%;
   border:1px solid silver;
   border-top: none;
   box-sizing: border-box;
   list-style: none;
   position: absolute;
   top:31px;
   right:0;
  }
  .items{
   margin-top:8px;
   padding: 2px;
   cursor: pointer;
  }
  .items:hover{
   background: #ddd;
  }
  .isSelectedText{
   display: inline-block;
   width:90%;
  }
  .dsn{
   display: none;
  }

<div class="container">
 <span class="text-container">最爱的水果</span>
 <div class="multipleSelect selectContainer">
  <input type="text" class="selectedContent">
  <div class="dropDown-toggle">选择</div>
  <ul class="dropDown-menu dsn">
   <li class="items">
    <span class="isSelectedText">苹果</span>
    <span class="isSelected"><input type="checkbox"></span>
   </li>
   <li class="items">     
    <span class="isSelectedText">梨</span>
    <span class="isSelected"><input type="checkbox"></span>
   </li>
   <li class="items">
    <span class="isSelectedText">橘子</span>
    <span class="isSelected"><input type="checkbox"></span>
   </li>
   <li style="text-align: right">
    <button type="button" class="confirmSelect">确定</button>
   </li>
  </ul>
 </div>
</div>

$('.isSelected input[type=checkbox]').on('click', function(){
   var selectedItems = $(this).parents('.dropDown-menu').prevAll('.selectedContent').val().split(' ');
   var thisItem = $(this).parent().prev().text();
   var isExisted = 0;
   var isChecked = $(this).is(':checked');
   if(isChecked){
    selectedItems.map(function(item, index){
     if(item === thisItem){
      isExisted++
     }
    });
    if(!isExisted){
     selectedItems.push(thisItem)
    }
   }
   else{
    selectedItems.map(function(item, index){
     if(item === thisItem){
      selectedItems.splice(index, 1);
     }
    });
   }
   $(this).parents('.dropDown-menu').prevAll('.selectedContent').val(selectedItems.join(' '));
  })
  $('.confirmSelect').on('click', function(){
   $(this).parents('.dropDown-menu').addClass('dsn');
  })
  $('.dropDown-toggle').on('click', function(){
   $(this).next().toggleClass('dsn')
  });