<!DOCTYPE html>
<html manifest="/m.appcache">
页面ICON image/x-icon|image/gif
<link rel="shortcut icon" href="http://example.com/favicon.ico" type="image/vnd.microsoft.icon">
<link rel="icon" href="http://example.com/favicon.ico" type="image/vnd.microsoft.icon">
<link rel="Bookmark" href="favicon.ico" /> png
预加载
<link rel="prefetch" href="./img/ad/home_03.jpg" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=0">
<meta name="format-detection" content="telephone=no">
<meta http-equiv="refresh" content="5">这个表示当前页面每5秒钟刷一下，刷一下~
<meta http-equiv="refresh" content="2; url='/'">这个表示当前页面2秒后跳到首页~
<script defer src="myscript.js"></script> async（两个都是异步,加载）defer加载后，等待执行。async下载完就执行。
默认为同步加载，后执行.