原生JS实现HTML下拉多选框的方法

核心代码实现与结构

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>www.jb51.net jQuery模拟select</title>
 <script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
 <style>
 body {
 font: normal 14px/100% "Andale Mono", AndaleMono, monospace;
 color: #fff;
 padding: 50px;
 width: 300px;
 margin: 0 auto;
 background-color: #374954;
}
.dropdown {
 position: absolute;
 top:50%;
 transform: translateY(-50%);
}
a {
 color: #fff;
}
.dropdown dd,
.dropdown dt {
 margin: 0px;
 padding: 0px;
}
.dropdown ul {
 margin: -1px 0 0 0;
}
.dropdown dd {
 position: relative;
}
.dropdown a,
.dropdown a:visited {
 color: #fff;
 text-decoration: none;
 outline: none;
 font-size: 12px;
}
.dropdown dt a {
 background-color: #4F6877;
 display: block;
 padding: 8px 20px 5px 10px;
 min-height: 25px;
 line-height: 24px;
 overflow: hidden;
 border: 0;
 width: 272px;
}
.dropdown dt a span,
.multiSel span {
 cursor: pointer;
 display: inline-block;
 padding: 0 5px 2px 0;
}
.dropdown dd ul {
 background-color: #4F6877;
 border: 0;
 color: #fff;
 display: none;
 left: 0px;
 padding: 2px 15px 2px 5px;
 position: absolute;
 top: 2px;
 width: 240px;
 list-style: none;
 height: auto;
 overflow: auto;
 margin-top:30px;
}
.dropdown span.value {
 display: none;
}
.dropdown dd ul li a {
 padding: 5px;
 display: block;
}
.dropdown dd ul li a:hover {
 background-color: #fff;
}
button {
 background-color: #6BBE92;
 width: 302px;
 border: 0;
 padding: 10px 0;
 margin: 5px 0;
 text-align: center;
 color: #fff;
 font-weight: bold;
}
 </style>
</head>
<body>
<dl class="dropdown">
 <dt>
 <div style="">
  <div class="multiSel" style="width:150px;background:#fff;padding: 8px 20px 5px 10px;height:20px;color:#000;float:left;"></div>
  <div class="mydropdown" style="width:50px;background:#fff;padding: 8px 20px 5px 10px;height:20px;color:#000;float:left;">sss</div>
 </div>
 </dt>
 <dd>
  <div class="mutliSelect">
   <ul>
    <li>
     <input type="checkbox" value="Apple" />Apple</li>
    <li>
     <input type="checkbox" value="Blackberry" />Blackberry</li>
    <li>
     <input type="checkbox" value="HTC" />HTC</li>
    <li>
     <input type="checkbox" value="Sony Ericson" />Sony Ericson</li>
    <li>
     <input type="checkbox" value="Motorola" />Motorola</li>
    <li>
     <input type="checkbox" value="Nokia" />Nokia</li>
   </ul>
  </div>
 </dd>
</dl>
<script>
 $(".dropdown dt .mydropdown").on('click', function() {
  $(".dropdown dd ul").slideToggle('fast');
 });
$(".dropdown dd ul li a").on('click', function() {
 $(".dropdown dd ul").hide();
});
function getSelectedValue(id) {
 return $("#" + id).find("dt a span.value").html();
}
$(document).bind('click', function(e) {
 var $clicked = $(e.target);
 if (!$clicked.parents().hasClass("dropdown")) $(".dropdown dd ul").hide();
});
$('.mutliSelect input[type="checkbox"]').on('click', function() {
 var title = $(this).closest('.mutliSelect').find('input[type="checkbox"]').val(),
 title = $(this).val() + ",";
 if ($(this).is(':checked')) {
 var html = '<span title="' + title + '">' + title + '</span>';
 $('.multiSel').append(html);
 } else {
 $('span[title="' + title + '"]').remove();
 }
});
 </script>
</body>
</html>