Don't Overlook Meta Tags: This HTML Element Has Many Uses

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Volume 14

No. 1 September/October 1998

Don't Overlook Meta Tags: This HTML Element Has Many Uses

Robyn Fizz and Deborah Levinson

If you're like most people who publish on the Web, you've probably heard about meta tags but aren't sure what they do. While these tags aren't required elements in Web page code, they can perform several useful tasks. This article gives a brief overview of their functionality and how to use them.

The prefix "meta" means, among other things, comprehensive or transcending. In HTML, meta tags let you specify information about your document as a whole. In practical terms, you can

Specify keywords and a description for your document that can help search engines rank the page within their listings

Instruct Web robots not to index a page

Supply a name and email address for the document's author

Set an expiration date for a page

Automatically redirect users to another document

A Few HTML Basics
Meta tags belong in the <head> section of an HTML document, before the <body> tag. They do not take a closing </meta> tag.

You can use several meta tags with different attributes within the same document. For the correct HTML code, see the examples in the screened box to the right. Make sure that your meta tags don't include line breaks, since these can cause some search engines to balk.

Keywords and Description
By indicating content, the keywords and description attributes aid search engine robots in ranking your pages. When you enter keywords for a page, each word or phrase should be separated by a comma. Remember to include synonyms and, when you use acronyms, to spell them out as well. In general, use a large number of keywords only on your site's index page. There's no need to add keywords to every page in your site - a few representative samples will do the job.

The description attribute returns your description of the page in place of the summary the search engine would ordinarily create (from the first several words it encounters on a page). Keep your descriptions accurate but short, under 20 words.

Be aware that a few search engines (most notably, Excite) ignore keyword and description attributes when weighting their rankings.

Robot Indexing Instructions
Sometimes, rather than trying to make your page more visible to search engines, you don't want a page to be indexed at all. In this instance, use the robots attribute with a value of "noindex, nofollow." "Noindex" tells the robot not to index the page, and "nofollow" tells it not to follow links from this page to other pages.

Author Information
You can specify a name and email address for the document's creator or maintainer. While many search engines don't pick up this information, it's still a good idea to include it.

Setting an Expiration Date
If your data changes on a regular basis, use the expire attribute to tell browsers when to look for a new copy of your document. In short, this attribute sets limits on how long your browser caches a file.

The date should be expressed as a two-digit day, three-letter month, and four-digit year. (While not standard practice, setting the expires attribute to "0" forces a reload each time.)

Web robots may delete expired documents from a search engine or schedule a revisit.

Automatic Redirects
A meta tag that uses the refresh attribute lets you automatically redirect users to a different page. This is helpful in cases where a URL has changed and you need a quick way to let people know about it.

Since some older browsers don't recognize this tag, it's important that you also place an actual HTML link to your new file on the redirection page.

In the code for automatic redirects (see the box below), the number before the semicolon represents the time, in seconds, before the browser loads the specified URL. Using "0" will cause a nearly instantaneous redirect to the other page.

More about Meta Tags
The document "Using Meta Tags at MIT" served as a source for this article and provides more in-depth detail, including a template for a simple re-direction page. It's online at http://web.mit.edu/ist/web/reference/create/metatags.html. You can view the source for this document to see assorted meta tags in use.

You can also learn more about meta tags by visiting webdeveloper.com. This site offers a Meta Tag Tutorial at http://www.webdeveloper.com/categories/html/html_metatags.html

and a Meta Tag Resource Page at http://webdeveloper.com/categories/html/html_metatag_res.html

In HTML: A Meta Tag Sampler

Keywords and Description
<meta name="keywords" content="meta tags, HTML, attributes">
<meta name="description" content="article on using meta tags">

Robots
<meta name="robots" content="noindex,nofollow">

Author
<meta name="author" content="Deborah Levinson">
<link rev="made" href="mailto:cwis-help@mit.edu">

Expires
<meta http-equiv="expires" content="01 Jul 1999">

Refresh (Automatic Redirect)
<meta http-equiv="refresh" content="0;URL=web.mit.edu/ist/isnews">

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