xhtml
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN" “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" dir="ltr" lang="zh-CN" xml:lang="zh-CN"> ???<head> ???????<meta http-equiv="content-type" content="text/html; charset=utf-8"> ???????<meta name="author" content="ChenYu"> ???????<meta name="keywords" content="xx,xx,xx"> ???????<meta name="description" content="xxxx"> ???????<script type="text/javascript" src=""></script> ???????<link rel="stylesheet" type="text/css" href=""> ???????<title>xxxx</title> ???</head><html/>
html5
<!DOCTYPE html><html lang="zh-CN"> ???<head> ???????<meta charset="utf-8"> ???????<meta name="author" content="ChenYu"> ???????<meta name="keywords" content="xx,xx,xx"> ???????<meta name="description" content="xxxx"> <!--[if lt IE 7 ]><html class="ie6"><![endif]-->
<!--[if IE 7 ]><html class="ie7"><![endif]-->
<!--[if IE 8 ]><html class="ie8"><![endif]-->
<!--[if IE 9 ]><html class="ie9"><![endif]-->
<!--[if (gt IE 9)|!(IE)]><html><![endif]-->
<!--STATUS OK-->
???????
???????<script type="text/javascript" src=""></script> ???????<link rel="stylesheet" href=""> ???????<title>xxxx</title> ???</head><html/>
xhtml、html5常用头部head写法
原文地址：https://www.cnblogs.com/JDotNet/p/3458564.html