console 命令行工具 X clear

console

var Gid = document.getElementById;
var showArea = function() {
  Gid('show').innerHTML = "<h3>省" + Gid('s_province').value + " - 市" + Gid('s_city').value + " - 县/区" + Gid('s_county').value + "</h3>"
}
Gid('s_county').setAttribute('onchange', 'showArea()');

<div class="top">
	<h1>全国城市三级联动</h1>
</div>
<div class="info">
	<div>
	<select id="s_province" name="s_province"></select>  
    <select id="s_city" name="s_city" ></select>  
    <select id="s_county" name="s_county"></select> 
    <script type="text/javascript">_init_area();</script>
    </div>
    <div id="show"></div>
</div>

body {
  background: #EEEEEE;
  margin: 0;
  padding: 0;
  font-family: "微软雅黑", Arial, Helvetica, sans-serif;
}

a {
  color: #006600;
  text-decoration: none;
}

a:hover {
  color: #990000;
}

.top {
  margin: 5px auto;
  color: #990000;
  text-align: center;
}

.info select {
  border: 1px #993300 solid;
  background: #FFFFFF;
}

.info {
  margin: 5px;
  text-align: center;
}

.info #show {
  color: #3399FF;
}

.bottom {
  text-align: right;
  font-size: 12px;
  color: #CCCCCC;
  width: 1000px;
}

button {
  border: 1px solid #ccc;
  cursor: pointer;
  display: block;
  margin: auto;
  position: relative;
  top: 100px;
}

本项目引用的自定义外部资源

area.js