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HTML basic grammar and semantic writing rules and examples

陈政宽～Original: 2017-06-28 14:03:351581browse

This article organizes the basic syntax and semantics of HTML and provides examples. Friends who need it can refer to it

DOCTYPE

DOCTYPE(Document Type)

This statement is located at the very beginning of the document, before the html tag. This tag tells the browser which HTML or XHTML specification the document uses.

DTD(Document Type Definition)

The declaration starts with 1a309583e26acea4f04ca31122d8c535, it is not case sensitive, there is no content in front, if Having other content (except spaces) will cause the browser to turn on quirks mode in IE to render web pages. Public DTD, the name format is registration // organization // type tag // language, registration refers to whether the organization is registered by the International Organization for Standardization (ISO), + means yes, - means no. Organization is the name of the organization, such as: W3C. The type is usually DTD. A tag specifies a description of the public text, that is, a unique descriptive name for the referenced public text, which can be followed by a version number. The last language is the ISO 639 language identifier of the DTD language, such as: EN means English, ZH means Chinese. XHTML 1.0 can declare three DTD types. Represents strict version, transitional version, and framework-based HTML document respectively.

HTML 4.01 strict

e59f3f52655b814e6342df6232818ae7

HTML 4.01 Transitional

79556516d22f9c9265348cb77b531489

HTML 4.01 Frameset

5d531b0f74588d6ac431683c41976ae0

HTML5 Document Type

8b05045a5be5764f313ed5b9168a17e62fd01ee1352baefb8b90cb4a7d393c18

meta

Declare the character encoding used in the document

Before html5

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
html5
<meta charset="utf-8">

SEO optimization

Title

b2386ffb911b14667cb8f0f91ea547a7 your title6e916e0f7d1e588d4f442bf645aedb2f

Page description

ca826600512b13c31f7bcce7de165226

Keywords

ec9afc83b8be120f8a2d5453c4ad3375

Web author

3c82f6477a44903bbca6fdbf2e49d142

Web search engine indexing method

bcb4b6290d88db82208d69650f8f8693

follow Follow the link and analyze the target web page. This is the default behavior and can be ignored.

index Index the web page. This is the default behavior and can be ignored.

noodp does not use the Open Directory Project to create content descriptions.

noydir does not use Yahoo Directory to create content descriptions.

noarchive does not allow search engines to display cached versions of content.

cache allows search engines to display cached versions of content.

Nocache does not allow search engines to display cached versions of content.

Tags

define the structure of the document and make the markup of the document more semantic.

html5 demo
<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8">
 <title>html5 demo</title>
 </head>
 <body>
 <header>
  <h1>html5 demo</h1>
  <nav>
  <ul>
   <li>nav1</li>
   <li>nav2</li>
  </ul>
  </nav>
 </header>
 <section>
  <h1>article aside</h1>
  <article>article</article>
  <aside>aside</aside>
 <section>
 <footer>footer</footer>
 </body>
</html>

tips

html5 tags are more abundant and complete. The p tag seems to be of little use, but if you just want to add a style to the document, at this time p That’s where labels come in handy.

There will be some differences in the default styles of tags in different browsers. In order for a web page to have the same effect in different browsers, you usually need to format the tag style first

@charset "utf-8";
html{margin:0;padding:0;border:0}a,abbr,acronym,address,article,aside,blockquote,body,caption,code,dd,del,dfn,dialog,p,dl,dt,em,fieldset,figure,footer,form,h1,h2,
h3,h4,h5,h6,header,hgroup,iframe,img,label,legend,li,nav,object,ol,p,pre,q,section,span,table,tbody,td,tfoot,th,thead,tr,ul{margin:0;padding:0;border:0;
font-size:100%;font:inherit;vertical-align:baseline}article,aside,details,dialog,figcaption,figure,footer,header,hgroup,menu,nav,section{display:block}body
{line-height:1.5;background:#fff}table{border-collapse:separate;border-spacing:0}caption,td,th{text-align:left;font-weight:400;float:none!important}table,td,
th{vertical-align:middle}blockquote:after,blockquote:before,q:after,q:before{content:&#39;&#39;}blockquote,q{quotes:"" ""}a img{border:none}a{text-decoration:none}:
focus{outline:0}

If you want To use the html5 tag in a browser that does not support html5, you need to add a small piece of JavaScript code

<script>
 document.createElement(&#39;header&#39;);
 document.createElement(&#39;nav&#39;);
 document.createElement(&#39;section&#39;);
 document.createElement(&#39;aside&#39;);
 document.createElement(&#39;article&#39;);
 document.createElement(&#39;footer&#39;);
</script>

The tag editable attribute contenteditable

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I hope the above article content will be helpful to all my friends

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