HTML & XHTML: The Definitive Guide, 6th Edition

Client-Pull Documents

Client-pull documents are relatively easy to prepare, and you can run them locally without requiring an HTTP server. That's because the client-pull document has the browser request and load another document, even if from local storage. All you need to do is embed a <meta> tag into the header of your HTML or XHTML document. The special tag tells the client browser to display the current document for a specified period of time and then load and display an entirely new one, just as though the user had selected the new document from a hyperlink. (Note that currently there isn't an easy way to change just a portion of a document dynamically using client-pull, though you could use frames if you wanted a split-screen effect.) [<meta>, 6.8.1]

Uniquely Refreshing

Client-pull dynamic documents work with all the popular browsers because they respond to a special HTTP header field called Refresh.

You may recall from previous discussions that whenever an HTTP server sends a document to the client browser, it precedes the document's data with one or more header fields. One header field, for instance, contains a description of the document's content type, used by the browser to decide how to display the document's contents. For example, the server precedes HTML documents with the header "Content-type: text/html," whose meaning should be fairly obvious.

As we discussed in Chapter 6, you can add your own special fields to an HTML document's HTTP header by inserting a <meta> tag ...