How to open XHTML? What is the content of XHTML specification?

How to open XHTML? What is the specification content of XHTML? This article will introduce to you in detail how to open HTML and what the content of the specification is.

First let us take a look at how to open XHTML:

Use You can see the effect with a browser, you can see the code with Notepad, or the professional Dreamweaver

xhtml is a language, generally files are html or htm, excluding dynamically generated pages

XHTML writing specification

This is a valid XHTML file writing specification:

A file that conforms to the XHTML standard can be called valid. This can ensure that the XHTML file code Coordination can also make files easier to process without having to ensure consistency in compilation by various browsers. The W3C verification service can verify whether the file is valid. In fact, many website development tools (such as Dreamweaver) support document verification based on W3C standards.

XHTML language must conform to the XML format, for example

Attribute names must be lowercase

　　错误的：<table WIDTH="100%"> 
　　正确的：<table width="100%">

Use double quotes for attribute values

　　错误的：<table width=100%>
　　正确的：<table width="100%">

Attribute abbreviations are not allowed

　　错误的：<input checked> <input readonly> <input disabled> <option selected> <frame noresize> 　
　　正确的：<input checked="checked" /> <input readonly="readonly" /> <input disabled="disabled" /> <option selected="selected" /> <frame noresize="noresize" />

Use the id attribute to replace the name attribute

　　这是错误的：<img src="picture.gif" name="picture1" /> 
　　这是正确的：<img src="picture.gif" id="picture1" />

Note: For lower version browsers, you should use both the name and id attributes at the same time, and make their values ​​​​the same , like this:

<img src="picture.gif" id="picture1" name="picture1" />

This is a list of abbreviated attributes in HTML and how they should be written in XHTML:

HTML XHTML 
compact compact="compact" 
checked checked="checked"
declare declare="declare"
readonly readonly="readonly"
disabled disabled="disabled"
selected selected="selected"
defer defer="defer"
ismap ismap="ismap"
nohref nohref="nohref"
noshade noshade="noshade"
nowrap nowrap="nowrap"
multiple multiple="multiple"
noresize noresize="noresize"

The purpose of these practices is to enable an XHTML web page to be Browsers compile correctly and faster. Valid XHTML file

Contents of XHTML specification:

1. All tags must have a corresponding closing tag

In the past in HTML, you could open many tags, such as

and

without necessarily writing the corresponding

and

to close them. But this is not legal in XHTML. XHTML requires a strict structure and all tags must be closed. If it is a separate unpaired tag, add a "/" at the end of the tag to close it. For example:

---

2. The names of all tag elements and attributes must be in lowercase

Unlike HTML, XHTML is case-sensitive,