Metadata is information placed within a document in order to describe the document itself. Metadata is used to help search engines index web pages. By using tags which are not displayed by the browser, information about the page or site can be included in order to better describe its contents. In particular, it may contain information about the document's author(s), its expiration date, the language used, etc.
These "Metatags" are special tags found in the header of the document (i.e. the HEAD tag found before the BODY tag), mainly for supplying information so that search engines can index the web page.
There are two different types of metatags:
<META NAME="Tag Name" CONTENT="Attribute">
<META HTTP-EQUIV="Tag Name" CONTENT="Attribute">
Multiple metatags can be included, one after another, in a page header.
| Tag Name | Attribute | Use |
|---|---|---|
| Author | "Information about the author" | Information about the author of the page |
| Copyright | Copyright information | Provides copyright information |
| Description | "Description of your site" | Gives information to display in search results. |
| Expires | never "date when the page expires" |
Tells the robot what date the page will expire on. |
| Generator | Software name | Name of the HTML editor which generated the web page. |
| Keywords | "keyword, keyword, etc." | Keywords describing the Web page. |
| Rating | general | Type of content (target audience). |
| Rev | Your@e-mail | Webmaster's e-mail address. |
| Revisit-after | "x days" where x is the number of days | How long before the robot visits again |
| Robots | all none |
Lets all robots index the page Prevents robots from indexing it |
| Subject | "Page subject" | Specifies the subject of the page |
| Tag Name | Attribute | Use |
|---|---|---|
| Pragma | no-cache | Prevents browser from keeping the page in its cache |
| Refresh | x; URL="address" | Loads another page (located at the URL specified) after waiting x seconds. |
| Robots | all follow index nofollow noindex none |
Lets the robot index the entire page (default) Lets the robot follow links on the page Lets the robot index the page Prevents the robot from following links Prevents the robot from indexing the page Stops the robot from indexing the site |
| Window-target | _blank _top |
Forces the browser to display the page in a new window Displays the page full-size in a new window (not in a frame) |