Client-Pull Documents
Client-pull
documents are relatively easy to prepare. All you need to do is embed
a <meta> tag in 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 if the user had selected the new
document from a hyperlink. (Note that currently there is no way to
change just a portion of a document dynamically using client-pull.)
[<meta>]
Uniquely Refreshing
Client-pull dynamic documents work with
Netscape and Internet Explorer because the browsers 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 into its
<head>. [<meta>]
The HTTP Refresh field implements client-pull
dynamic HTML documents, enabled by the
<meta> tag format:
<meta http-equiv="Refresh" content="field value">
The tag’s
http-equiv
attribute tells the HTTP server to include the ...
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