1.Browsers display <strong> as <b> ,<em> and as<i> .
However, there is a difference in the meaning of these tags: <b>and<i> defines bold and italic text,
but<strong> and<em> means that the text is "important".
在浏览器中，<strong>和<b>，<em>和<i>的效果是一样的，但事实是他们是不一样的，<b>和<i>定义了字体的粗细以及斜体，但<strong>和<em>定义了是文本的重要性。
2.The HTML element defines an abbreviation or an acronym.
Marking abbreviations can give useful information to browsers, translation systems and search-engines.
HTML< abbr>元素定义了缩写或首字母缩写词。
标记缩略语可以给浏览器、翻译系统和搜索引擎提供有用的信息。
3.链接中的target属性：
Target Value Description
_blank Opens the linked document in a new window or tab
_self Opens the linked document in the same frame as it was clicked (this is default)
_parent Opens the linked document in the parent frame
_topOpens the linked document in the full body of the window
framename Opens the linked document in a named frame
_blank值，在新的窗口和tab栏打开链接网页；_self值，在所在页面打开链接，默认属性值；_parent值，在父级的框架中打开网页链接;
4.语义化标签
<header> - Defines a header for a document or a section
<nav> - Defines a container for navigation links
<section> - Defines a section in a document
<article> - Defines an independent self-contained article
<aside> - Defines content aside from the content (like a sidebar)
<footer> - Defines a footer for a document or a section
<details> - Defines additional details
<summary> - Defines a heading for the <details> elemen
5.base标签
<base> 标签为页面上的所有链接规定默认地址或默认目标。
通常情况下，浏览器会从当前文档的 URL 中提取相应的元素来填写相对 URL 中的空白。
使用 <base> 标签可以改变这一点。浏览器随后将不再使用当前文档的 URL，而使用指定的基本 URL 来解析所有的相对 URL。这其中包括 <a>、<img>、<link>、<form> 标签中的 URL。
6.URL(Uniform Resource Locator)
syntax rules:
scheme://prefix.domain:port/path/filename
Explanation:
scheme - defines the type of Internet service (most common is http)
prefix - defines a domain prefix (default for http is www)
domain - defines the Internet domain name (w3schools.com)
port - defines the port number at the host (default for http is 80)
path - defines a path at the server (If omitted: the root directory of the site)
filename - defines the name of a document or resourc
Scheme:
7.GET和POST方法
When you use GET, the form data will be visible in the page address.
当你使用GET的方法，表单的数据将被呈现在网页的地址栏。
GET is best suited to short amounts of data. Size limitations are set in your browser.
GET最适合短数据量大小，在你的浏览器可限制长度。
POST offers better security because the submitted data is not visible in the page address.
POST更加安全，因为提交的数据不会呈现在网页的地址栏。
