What Is a http-equiv META Tag/Element? - XHTML 1.0 Tutorials - Document Structure and Head Level Tags

a http-equiv meta element is a special meta element that provides information equivalent to HTTP headers. A http-equiv meta element must include the "http-equiv" attribute as, http-equiv="Content-Type". Here is some good examples:

  <meta http-equiv="Content-Type" content="text/html;
    charset=UTF-8" />
  <meta http-equiv="Refresh" content="3; 
    URL=http://dev.fyicenter.com/" />
  <meta http-equiv="Expires" content="Sun, 22 Mar 1998
   16:18:35 GMT" />

XHTML browsers and search engines are all respecting http-equiv meta elements. So it is important to code the keywords meta element properly in your XHTML documents following rules below:

• Include http-equiv meta elements in XHTML documents as needed. Do not include all http-equiv meta elements in every XHTML documents.
• Attribute "http-equiv" must contain valid HTTP headers defined in HTTP protocol.
• Attribute "content" must contain valid values that matches the HTTP header specified in "http-equiv".
• http-equiv="Content-Type" is used to specify the document type, and character set.
• http-equiv="Refresh" is used to specify a refresh with a waiting period and a URL.
• http-equiv="Expires" is used to an expiration time of the document.