About the role of meta in html (collected and compiled from the Internet)_HTML/Xhtml_Web page production

W3Cschool explains this as follows

elements can provide meta-information about the page, such as descriptions and keywords for search engines and update frequency. The

tag is located at the head of the document and contains no content. The tag's attributes define the name/value pairs associated with the document.

Differences between HTML and XHTML

In HTML, the tag does not have a closing tag.

In XHTML, the tag must be closed properly.

Tips and Notes:

Note: The tag is always inside the head element.

Note: Metadata is always passed in name/value pairs.

name attribute

The name attribute provides the name in a name/value pair. Neither HTML nor XHTML tags specify any predefined names. In general, you are free to use names that are meaningful to you and to readers of the source document.

"keywords" is a name that is often used. It defines a set of keywords for the document. Some search engines use these keywords to classify documents when they encounter them.

A meta tag like this may be helpful for getting indexed by search engines:

http-equiv attribute

http-equiv attribute is name/ The value pair provides the name. and instructs the server to include name/value pairs in the header of the MIME document to be sent to the browser before sending the actual document.

When the server sends a document to the browser, it first sends a number of name/value pairs. Although some servers send many of these name/value pairs, all servers send at least one: content-type:text/html. This tells the browser to prepare to accept an HTML document.

When using the tag with the http-equiv attribute, the server will add the name/value pair to the content header sent to the browser.

content attribute

content attribute provides the value in a name/value pair. The value can be any valid string.

The content attribute should always be used together with the name attribute or the http-equiv attribute.

scheme attribute

scheme attribute is used to specify the scheme to be used to translate the attribute value. This scheme should be defined in the profile file specified by the profile attribute of the tag.

meta is used to simulate the response header message of the HTTP protocol in HTML documents. The meta tag is used in and on web pages. The meta tag has many uses. There are two attributes of meta: name and http-equiv. The name attribute is mainly used to describe web pages, corresponding to content (web page content), so that search engine robots can find and classify them (at present, almost all search engines use online robots to automatically find meta values ​​to classify web pages). The most important of these are description (description of the site on search engines) and keywords (categorization keywords), so a meta value should be added to each page. The more commonly used ones are as follows:

name attribute

1. is used to describe the generation tool (such as Microsoft FrontPage 4.0), etc.;

2. Describe the keywords of your webpage to the search engine;

　3. Tell the search engine the main content of your site;

　4. Tell the search engine your site The author of the production;

5.

The attributes are described as follows:

Set to all: the file will be retrieved, and the links on the page can Be queried;

Set to none: the file will not be retrieved, and the links on the page cannot be queried;

Set to index: the file will be retrieved;

Set to follow: links on the page can be queried;

Set to noindex: files will not be retrieved, but links on the page can be queried;

Set to noindex nofollow: The file will not be retrieved, but links on the page can be queried.

HTTP-equiv attribute

1.

and are used to describe the text and language used in making the homepage;

And For example, English is the ISO-8859-1 character set, and there are also BIG5, utf-8, shift-Jis, Euc, Koi8-2 and other character sets;

　2. Timing allows the web page to display at the specified time Within n, jump to the page http://yourlink;

3. can be used to set the expiration time of the web page. Once it expires, it must be called again on the server. It should be noted that the GMT time format must be used;

4. is used to set the browser to prevent the browser from accessing the page content from the cache of the local machine. Once you leave the webpage after setting, it cannot be retrieved from the cache;

　5. Cookie settings, if the web page expires, the saved cookies will be deleted. It should be noted that the GMT time format must be used;

6. For web page rating, there is a content setting in IE's internet options that can prevent browsing of some restricted websites, and the restriction level of the website It is set through the meta attribute;

7. forces the page to be displayed as an independent page in the current window, which can prevent your own web page from being called as a frame page by others;

8. and set special effects when entering and leaving the page. This function is the "format/web page transition" in FrontPage, but the added page cannot be a frame page.