html中的重点 （表单提交、的使用、CSS样式优先权）

1. 表单登录

        <div class="top-tt">
            <form action="/home.html" method="post">
                <label for="username"  >用户名：</label>
                <input type="text"  name="username" id="username"  placeholder="请输主用户名">
                <label for="email"  >Email：</label>
                <input type="text"  name="email" id="email"  placeholder="请输入邮箱">
                <label for="pw" >密   码：</label>
                <input type="text" name="pw" id="pw" placeholder="请输入8位以上密码">
                <input type="submit" value="登 录">
            </form>
        </div>

2. <iframe>表单使用

<!-- 导航 -->
    <div class="nav">
        <div class="nav-1200">
            <a class="item" href="/" >首页</a>
        <a class="item" href="http://www.php.cn" target="content" >班花跳舞视频</a>  
        <a class="item" href="https://www.ifeng.com/" target="content" >校花跳舞视频</a>
     </div>
    </div>
    <div class="index-box">
        <div class="box-iframe">
            <iframe class="" src="https://www.sina.com.cn" frameborder="2" name="content"></iframe>
        </div>
    </div>

3. CSS样式优先排序

    <style>
        .ddv{
            display: flex;
            justify-content: center;
            margin-top: 10px;
        }
        .hao{
            width: 100px;height:100px;background: rgb(219, 64, 180);
        }
        #haohao{width:100px;height: 100px;background-color: aqua;}
    </style>
    <div class="ddv">
        <div class="hao" >
                <p>1</p>
        </div>
        <div class="hao" id="haohao"  >
            <p>2</p>
        </div>
        <div class="hao" id="haohao" style="width:100ox;height:100px;background:red;"  >
            <p>3</p>
        </div>