When using JavaScript in your Web pages, you should keep in mind that a user’s browser might not support JavaScript. This could either be because the browser is old or because the user disabled JavaScript. Either way, the tag provides a solution. Any HTML enclosed between and will only be displayed if JavaScript is unavailable. This solution works in Navigator 1.22 as well as 3.0 and above, but not in Navigator 2.x.
You can also alert users that JavaScript is required and provide them with help on either downloading a compatible browser or re-enabling JavaScript support. One solution is to include a tag inside a set of tags in the portion of the page, which will re-direct users without JavaScript (and those using Navigator 2.02) to a different page.
This document requires JavaScript. If JavaScript is unavailable you'll be automatically re-directed to an alternate page.