Database Reference
In-Depth Information
<BODY>
<H1>Headings Layer 1</H1>
<P>This is section 1.</P>
<H2>Headings Layer 2</H2>
<P>This is section 1.1.</P>
</BODY>
</HTML>
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or Dynamic HTML. Dynamic
HTML extends HTML using a combination of technologies. This combi-
nation of technologies exists in the document object model plus client- and
server-based scripting languages such as JavaScript, Active Server Pages
(ASP), and Java Servlets (JSP), among many others. DHTML allows cre-
ation of Web pages with much more flexibility than HTML.
The flexibility of DHTML leads us to the definition of the eXtensible
Markup Language (XML). XML essentially allows for a context-sensitive
interface. What is this in English? It allows Web pages to vary based on who
is reading them and the specific needs of the person browsing a Web page.
Thus XML can be used as a Web page scripting language, sensitive to
unique requirements of individual people.
Ultimately, XML
An extension of HTML is DHTML
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is not limited to a predefined set of tags as in
HTML. XML allows for creation of customized tags, on the fly, based on
data content, and more specifically based on the content of a database. The
content of a database is flexible in terms of what information is stored in
that database. Therefore, the advantages of using XML are flexibility for
data and Web page integration, open standards, enhanced scalability, and
compression in Web page delivery. Additionally, the order of tags within
an XML document is not that important to XML, apart from the fact that
all elements must be contained within other elements, except for the root
node, of course. eXtensible Style Sheets (XSL) extend XML, perhaps in a
similar way to that in which DHTML extends HTML. XSL allows for
consistent patterns or pictures to be applied to data with consistent pat-
terns, namely rows from a query. Once again, what is all that in English? It
is best to demonstrate.
The following script shows a simple XML document, listing things
about various cities. Figure 17.1 shows the same code but from the perspec-
tive of what this document looks like in a Web browser.
<?xml version="1.0"?>
<world>
