# HTML head 常用标签
## HTTP Headers 相关
### 字符编码
定义文档字符编码：
```markup
```
> **Tips:**
>
> `` 元素必须包含在 `` 元素中并且在HTML代码的前 1024 个字节内，因为某些浏览器在选择编码之前只查看前面这些字节。
>
> `` 元素只是 [algorithm to determine the character se](http://www.whatwg.org/specs/web-apps/current-work/multipage/parsing.html#encoding-sniffing-algorithm)t 中的一部分。 HTTP的 Content-Type 头部以及任何 Byte-Order Marks 元素都优先于此元素。
### 页面刷新
倒计时刷新页面：
```markup
```
倒计时跳转页面：
```markup
```
### DNS 预解析
开启 DNS 预解析，并指定预解析的域名：
```markup
```
## SEO 相关
### 页面信息
页面标题：
```markup
Title
```
页面关键字（一般不超过 874 个字符）：
```markup
```
页面描述（一般不超过 150 个字符）：
```markup
```
### 搜索引擎
约定搜索引擎爬虫行为：
```markup
```
## 桌面浏览器兼容
### 双核浏览器设置
国内双核浏览器设置：
```markup
```
### IE9 以下浏览器
指定渲染模式：
```markup
```
## 移动设备适配
### 移动视口适配
设置移动设备初始视口大小：
```markup
```
### Safari 浏览器
关闭 iOS Safari (UIWebView) 自动识别：
```markup
```
Smart App Banner:
```markup
```
### QQ 浏览器
QQ 浏览器设置：
```markup
```
### UC 浏览器
UC 浏览器设置：
```markup
```
### 百度移动适配
移动端百度搜索结果跳转适配：
```markup
```
## 链接外部资源
加载链接的外部资源：
```markup
```
## 参考文献
* [HTML（超文本标记语言）](https://developer.mozilla.org/zh-CN/docs/Web/HTML)
* [meta](https://developer.mozilla.org/zh-CN/docs/Web/HTML/Element/meta)
* [What does meta http-equiv=“X-UA-Compatible” content=“IE=edge” do?](https://stackoverflow.com/questions/6771258/what-does-meta-http-equiv-x-ua-compatible-content-ie-edge-do)
* [Using meta tags to turn off caching in all browsers?](https://stackoverflow.com/questions/1341089/using-meta-tags-to-turn-off-caching-in-all-browsers)
* [How to prevent caching in Internet Explorer](https://support.microsoft.com/en-us/help/234067/how-to-prevent-caching-in-internet-explorer)
* [Promoting Apps with Smart App Banners](https://developer.apple.com/library/archive/documentation/AppleApplications/Reference/SafariWebContent/PromotingAppswithAppBanners/PromotingAppswithAppBanners.html)
---
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