iframe简单应用和CSS选择器样式优先级
用iframe写一个简单后台版面
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>简单后台管理版式</title>
<style>
body{margin: 0px;padding: 0px;}
header{background-color: coral;height: 50px;padding: 10px;text-align: center;}
aside{background-color: darkgray;height: 400px;width: 150px;float: left;}
a{display: block;margin: 20px;}
main{background-color: darkkhaki;height: 400px;}
footer{height: 50px;background-color: darkseagreen;text-align: center;}
span{font-weight: 1.5em;padding-right: 20px;color: darkslategrey;}
</style>
</head>
<body>
<div>
<header><h2>WEB系统后台管理</h2></header>
<div>
<aside>
<a href="http://baidu.com" target="main">组织架构</a>
<a href="http://163.com" target="main">业务服务</a>
<a href="http://mail.163.com" target="main">业务规则</a>
<a href="http://www.jackli.top:82" target="main">系统管理</a>
</aside>
<main>
<iframe src="" srcdoc="<em>请选择功能</em>" name="main" frameborder="0" width="500px" height="400px"></iframe>
</main>
</div>
<footer>
<span>技术支持:php中文网学习心得</span>
<span><em>mail:123@qq.com</em></span>
<span><del>没有版权</del></span>
</footer>
</div>
</body>
</html>
结果图示
CSS样式来源及优先级,CSS选择器优先级示例
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>元素CSS样式四个来源</title>
<style>
span{margin-right: 20px;background-color: rgb(223, 217, 217);}
li{margin: 10px; }
.mycol{color: blue;}
#col{color: crimson;}
.col{color: darkblue;}
ol{color: rgb(15, 146, 15);}
</style>
</head>
<body>
<h3>CSS样式来源及优先级</h3>
<ul>
<li style="color: red;" class="mycol"><span>优先1</span>CSS样式来源: 行内样式为红色</li>
<li class="mycol"><span>优先2</span>CSS样式来源: 自定义样式为蓝色</li>
<li><span>优先3</span>CSS样式来源: 浏览器样式</li>
<li><span>优先4</span>CSS样式来源: 继承HTML</li>
</ul>
<h3>CSS选择器优先级</h3>
<ol>
<li id="col" class="col">
<span>优先级1(ID)</span>ID颜色优先于OL标签和类
</li>
<li class="col">
<span>优先级2(类)</span>类颜色优先于OL标签
</li>
<li >
<span>优先级3(标签)</span>继承OL标签颜色
</li>
</ol>
</body>
</html>