h12 HTML Meta Tags
HTML lets you specify metadata, which is additional important information about a document, in a variety of ways. The META elements can be used to include name/value pairs describing properties of the HTML document, such as author, expiry date, a list of keywords, document author etc.
The <meta> tag is used to provide this extra information. It's a self-closing element, meaning it doesn't require a closing tag but carries information within its attributes.
You can include one or more meta tags in your document based on what information you want to keep in your document but in general, meta tags do not impact the physical appearance of the document so from the appearance point of view, it does not matter if you include them or not.
Adding Meta Tags to Your Documents
You can add metadata to your web pages by placing <meta> tags inside the header of the document which is represented by <head> and </head> tags. A meta tag can have following attributes in addition to core attributes −
| S.No | Attribute & Description |
|---|---|
| 1 |
Name Name for the property. Can be anything. Examples include, keywords, description, author, revised, generator etc. |
| 2 |
content Specifies the property's value. |
| 3 |
scheme Specifies a scheme to interpret the property's value (as declared in the content attribute). |
| 4 |
http-equiv Used for http response message headers. For example, http-equiv can be used to refresh the page or to set a cookie. Values include content-type, expires, refresh and set-cookie. |
Specifying Keywords
You can use <meta> tag to specify important keywords related to the document and later these keywords are used by the search engines 搜索引擎（比如 百度，bing, google, etc）while indexing your webpage for searching purposes.
Example
Following is an example, where we are adding HTML, Meta Tags, and Metadata as important keywords about the document.
<!DOCTYPE html> <html> <head> <title>Meta Tags Example</title> <meta name="keywords" content="HTML, Meta Tags, Metadata" /> </head> <body> <p>Hello HTML5!</p> </body> </html>
Document Description
You can use <meta> tag to give a short description about the document. This again can be used by various search engines while indexing your webpage for searching purpose.
Example
<!DOCTYPE html> <html> <head> <title>Meta Tags Example</title> <meta name="keywords" content="HTML, Meta Tags, Metadata" /> <meta name="description" content="Learning about Meta Tags." /> </head> <body> <p>Hello HTML5!</p> </body> </html>
Document Revision Date
You can use <meta> tag to give information about when last time the document was updated. This information can be used by various web browsers while refreshing your webpage.
Example
<!DOCTYPE html> <html> <head> <title>Meta Tags Example</title> <meta name="keywords" content="HTML, Meta Tags, Metadata" /> <meta name="description" content="Learning about Meta Tags." /> <meta name="revised" content="Tutorialspoint, 3/7/2014" /> </head> <body> <p>Hello HTML5!</p> </body> </html>
Document Refreshing 刷新
A <meta> tag can be used to specify a duration after which your web page will keep refreshing automatically 自动刷新.
Example
If you want your page keep refreshing after every 5 seconds then use the following syntax.
<!DOCTYPE html> <html> <head> <title>Meta Tags Example</title> <meta name="keywords" content="HTML, Meta Tags, Metadata" /> <meta name="description" content="Learning about Meta Tags." /> <meta name="revised" content="Tutorialspoint, 3/7/2014" /> <meta http-equiv="refresh" content="5" /> </head> <body> <p>Hello HTML5!</p> </body> </html>
Page Redirection 重定向
You can use <meta> tag to redirect your page to any other webpage. You can also specify a duration if you want to redirect the page after a certain number of seconds.
Example
Following is an example of redirecting current page to another page after 5 seconds. If you want to redirect page immediately then do not specify content attribute.
<!DOCTYPE html> <html> <head> <title>Meta Tags Example</title> <meta name="keywords" content="HTML, Meta Tags, Metadata" /> <meta name="description" content="Learning about Meta Tags." /> <meta name="revised" content="Tutorialspoint, 3/7/2014" /> <meta http-equiv="refresh" content="5; url=http://www.tutorialspoint.com" /> </head> <body> <p>Hello HTML5!</p> </body> </html>
The above program will redirect you to Tutorialspoint home page after 5 seconds.
Setting Cookies 小甜饼
Cookies are data, stored in small text files on your computer and it is exchanged between web browser and web server to keep track of various information based on your web application need.
You can use <meta> tag to store cookies on client side and later this information can be used by the Web Server to track a site visitor.
Example
<!DOCTYPE html> <html> <head> <title>Meta Tags Example</title> <meta name="keywords" content="HTML, Meta Tags, Metadata" /> <meta name="description" content="Learning about Meta Tags." /> <meta name="revised" content="Tutorialspoint, 3/7/2014" /> <meta http-equiv="cookie" content="userid=xyz; expires=Wednesday, 08-Aug-15 23:59:59 GMT;" /> </head> <body> <p>Hello HTML5!</p> </body> </html>
If you do not include the expiration date and time, the cookie is considered a session cookie and will be deleted when the user exits the browser.
Note − You can check PHP and Cookies tutorial for a complete detail on Cookies.
Setting Author Name
You can set an author name in a web page using meta tag. See an example below −
Example
<!DOCTYPE html> <html> <head> <title>Meta Tags Example</title> <meta name="keywords" content="HTML, Meta Tags, Metadata" /> <meta name="description" content="Learning about Meta Tags." /> <meta name="author" content="Mahnaz Mohtashim" /> </head> <body> <p>Hello HTML5!</p> </body> </html>
Specify Character Set 字符集 编码
You can use <meta> tag to specify the character set used within the webpage.
Example
By default, Web servers and Web browsers use ISO-8859-1 (Latin1) encoding to process Web pages. Following is an example to set UTF-8 encoding 编码 −
<!DOCTYPE html> <html> <head> <title>Meta Tags Example</title> <meta name="keywords" content="HTML, Meta Tags, Metadata" /> <meta name="description" content="Learning about Meta Tags." /> <meta name="author" content="Mahnaz Mohtashim" /> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> </head> <body> <p>Hello HTML5!</p> </body> </html>
To serve the static page with traditional Chinese characters, the webpage must contain a <meta> tag to set Big5 encoding −
<!DOCTYPE html> <html> <head> <title>Meta Tags Example</title> <meta name="keywords" content="HTML, Meta Tags, Metadata" /> <meta name="description" content="Learning about Meta Tags." /> <meta name="author" content="Mahnaz Mohtashim" /> <meta http-equiv="Content-Type" content="text/html; charset=Big5" /> </head> <body> <p>Hello HTML5!</p> </body> </html>
