登录表单

<!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>
</head>
<body>
    <form action="check.php" method="post">
        <div>
            <label for="my-email">邮&nbsp箱:</label>
            <input type="email" id="my-email" name="email" value="" placeholder="php@163.com" autofocus required />
        </div>
        <br/>
        <div>
            <label for="psw">密&nbsp码:</label>
            <input type="password" id="psw" name="password" value="354875asfdf" placeholder="数字+字母" required />
        </div>
        <br/>
        <div>
            <button>登&nbsp录</button>
        </div>
    </form>
</body>
</html>

后台架构

<!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>
</head>
<body>
    <a href="https://map.baidu.com/search/%E6%AD%A6%E6%B1%89%E5%B8%82/@12725246,3558762.25,12z?querytype=s&da_src=shareurl&wd=%E6%AD%A6%E6%B1%89&c=218&src=0&pn=0&sug=0&l=13&b=(12695090,3538076;12729842,3560924)&from=webmap&biz_forward=%7B%22scaler%22:2,%22styles%22:%22pl%22%7D&device_ratio=2" target="bd-map">武汉市</a>
    <iframe srcdoc="<h3 style='color:#00a1e9'>点击城市查看位置</h3>" frameborder="1" width="400" height="500" name="bd-map"></iframe>
</body>
</html>

元素样式来源与优先级

<!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>
    <style>
        div {
            color: blue;
            color: rgb(247, 10, 10);
        }
        .div {
            color: rgb(8, 245, 126);
        }
    </style>
</head>
<body>
    <div >我是DIV
        <div class="div">我是class的DIV</div>
    </div>
</body>
</html>

1. 写一个登录表单,要求有邮箱,密码,登录按钮 2. 写一个简单后台架构: + 3. 实例演示元素样式来源与优先级

登录表单

后台架构

元素样式来源与优先级