Dynamic HTML: The Definitive Reference

Name

<BASE> — NN all IE all HTML all

Synopsis

<BASE>

End Tag: Forbidden

A BASE element is defined inside a document’s HEAD element to instruct the browser about the URL path to the current document. This path is then used as the basis for all relative URLs used to specify various SRC and HREF attributes in the document. The BASE element’s URL should be a complete URL, including the document name. The browser calculates the base URL path to the directory holding that document. For example, if you specify <BASE HREF="http://www.megacorp.com/products/index.html">, the HREF attribute of a link on that page to widgets/framitz801.html resolves to the full URL of http://www.megacorp.com/products/widgets/framitz801.html. Similarly, a relative URL can walk up the hierarchy with the dot syntax. For example, from the BASE element defined earlier, an IMG element in the index.html page might be set for SRC="../images/logo.jpg". That reference resolves to http://www.megacorp.com/images/logo.jpg.

By and large, today’s browsers automatically calculate the base URL of the currently loaded document, thus allowing use of relative URLs without specifying a BASE element. This is especially helpful when you are developing pages locally and don’t want to change the BASE element settings when you deploy the pages. The HTML 4.0 specification states that a document lacking a BASE element should by default use the current document’s URL as the BASE URL. Of course, this is only for true web pages, rather ...