console 命令行工具 X clear
console
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <link href="css/main.css" rel="stylesheet">
    <link rel="stylesheet" href="font-awesome/css/font-awesome.min.css">
    <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
    <style>
        * {
      margin: 0;
      padding: 0;

    }

    a {
      color: #000;
    }

    a:hover {
      text-decoration: none;
    }

    body {
      background: rgb(237, 237, 237);
    }

    /* 头部 */
    .head {
      width: 100%;
      padding: 0 10%;
    }

    .head p {
      width: 70%;
      float: left;
      margin-top: 20px;
      color: rgb(231, 0, 18);
      font-size: 20px;
    }

    .head>a {
      margin-top: 23px;
      margin-left: 1%;
      display: inline-block;
    }

    .head .btn-group {
      width: 15%;
      float: right;
      margin-top: 15px;
    }

    /* 导航 */
    .person {
      width: 80%;
      padding: 0 0 20px 0;
    }

    .person .nav {
      width: 22%;
      background: rgb(255, 255, 255);
      float: left;
    }

    /* 内容 */
    .main {
      width: 75%;
      background: rgb(255, 255, 255);
      float: right;
    }
    
    .panel button{margin: 0 0 15px 5px}
    .form-group input{
    border:0;
    box-shadow:none;
    text-align:right;

}
.form-group:focus input{
    border-color:#fff;
    box-shadow:none;
}
    </style>
</head>
<body onload="ff()">
  <!-- 头部 -->
  <div class="container head">
    <img class="pull-left" src="img/logo.png" alt="">
    <p>社区服务网站</p>
    <a href="login.html">登录</a>
    <a href="register.html">注册</a>
    <div class="btn-group">
      <a class="btn btn-danger" href="index.html" role="button">返回首页</a>

    </div>

  </div>
  <!-- End 头部 -->
  <!-- 个人 -->
  <div class="container person">
    <ul class="nav nav-pills nav-stacked">
      <li><a href="person.html">个人信息</a></li>
      <li class="active"><a href="update.html">信息修改</a></li>
      <li><a href="#">商品管理</a></li>
      <li><a href="#">商品发布</a></li>
      <li><a href="#">购物车</a></li>
      <li><a href="#">PHP</a></li>
    </ul>
    <div class="main">
<div class="panel panel-info">
    <div class="panel-heading"><strong>信息修改</strong></div>
    <form role="form">
    <ul class="list-group">
        <li class="list-group-item form-group"><label for="name"><strong>用户名</strong></label><span class="pull-right">
        <input type="text" class="form-control" id="name" value="XXX" required></span></li>
 <li class="list-group-item form-group"><label for="email"><strong>邮箱</strong></label><span class="pull-right">
        <input type="email" class="form-control" id="email" value="873226051@qq.com" required></span></li>
       <li class="list-group-item form-group"><label for="email"><strong>手机</strong></label><span class="pull-right">
        <input type="text" class="form-control" id="email" value="18787490001" required></span></li>
        <li class="list-group-item form-group"><label for="email"><strong>地区</strong></label><span class="pull-right">
         <select id="sel1" onchange="cc()">
            <option value="">请选择城市</option>
 </select>
        <select id="sel2">
            <option value="">请选择区</option>
        </select></span></li>
         <li class="list-group-item form-group"><label for="email"><strong>详细地址</strong></label><span class="pull-right">
        <input type="text" class="form-control" id="email" value="大连市甘井子区软件园路8号" required></span></li>
        
    </ul>

    <button type="submit" class="btn btn-primary">确认修改</button>
    <button type="reset" class="btn btn-danger">清除修改</button>
     
</form>
</div>
</div>
  </div>
  <!-- END 个人 -->
  <!-- 底部 -->
  <div class="container bottom"></div>
  <!-- END 底部 -->

  <script src="js/jquery.js"></script>
  <script src="js/bootstrap.min.js"></script>
  <script src="https://cdn.staticfile.org/jquery/2.1.1/jquery.min.js"></script>
	<script src="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>
<script>
        var shens = [ "中山区", "西岗区","甘井子区","沙河口区","高新区"];
        var chengs = [["和平区","沈河区","大东区","皇姑区","铁西区"],["中山区", "西岗区","甘井子区","沙河口区"]];
        function ff() {
            //doucument提供getElementById实现按照标签的id值进行查找，永远只返回第一个
            var ele = document.getElementById("sel1");
            console.log(ele.options);//可以获取当前select下的所有option
            //在js中如何创建<option>元素，document.createElement("option");
            for (let k = 0; k < shens.length; k++) {
                var op1 = document.createElement("option");
                op1.text = shens[k];//显示内容
                op1.value = "" + k;//提交数据
                console.log(op1);
                ele.options[k + 1] = op1;//将创建的option添加到options数组中则可以实现显示          
            }
        }

        function cc() {
            //首选获取sel1中选择的值？
            //获取下拉框中选中的值方法
            var ele = document.getElementById("sel1");//获取select元素
            var ele2 = document.getElementById("sel2");
            var kk = ele.selectedIndex;//获取下拉选项中的选项的索引值--序号
            //将索引值转换为提交值
            kk = ele.options[kk].value;
            //从二维数据中获取对应的城市选项
            var arr = chengs[kk];
            //将城市选项添加到sel2下拉选择框中
            //首先将下拉选项数据限制为合理的值，它会自动删除多余的选项
            ele2.options.length = arr.length + 1;
            for (let k = 0; k < arr.length; k++) {
                var op = document.createElement("option")
                op.text = arr[k];
                op.value = kk + "" + k;
                console.log(op)
                ele2.options[k + 1] = op;
            }
        }
    </script>

</body>
</html>