Vdiscussion » XML

Tags and Elements of HTML

admin — Tue, 17 Nov 2009 15:57:30 +0000

If you look at the first and last lines of the code for the last example, you will see pairs of angle brackets containing the letters . The two brackets and all of the characters between them are known as a tag, and there are lots of tags in the example. All of the tags in this example come in pairs; there are
opening tags and closing tags. The closing tag is always slightly different than the opening tag in that it has a forward slash character before the characters .

html

The special meaning these tags give is a description of the structure of the document. The opening tag says “This is the beginning of a heading” and the closing tag says “This is the end of a heading.”Without the markup, the words in the middle would just be another bit of text; it would not be clear that they formed the heading.
Now look at the paragraph of text about the company; it is held between an opening

tag and a closing

tag. And, you guessed it, the p stands for paragraph.

As you can see, the markup in this example actually describes what you will find between the tags, and the added meaning the tags give is describing the structure of the document. For example, between the opening

and closing

tags are paragraphs and between the

and

tags is a heading. Indeed, the whole HTML document is contained between opening and closing tags.
If you were wondering why there is a number 1 after the h , it is because in HTML and XHTML there are six levels of headings. A level 1 heading is sometimes used as the main heading for a document (such as a chapter title), which can then contain subheadings, with level 6 being the smallest. This allows you to structure your document appropriately with subheadings under the main heading.

Style sheet linking in XML

ma.vinothkumar — Thu, 12 Nov 2009 12:28:10 +0000

This technique, you link a style sheet to the XML document. A style sheet is a separate file that contains instructions for formatting the individual XML elements. You can use either a cascading style sheet (CSS)—which is also used for HTML pages—or an Extensible Stylesheet Language Transformations (XSLT) style sheet—which is considerably more powerful than a CSS and is designed specifically for XML documents.

Does XML Replace HTML ?

ma.vinothkumar — Thu, 12 Nov 2009 12:27:16 +0000

Currently, the answer to that question is no. HTML is still the primary language
used to tell browsers how to display information on the Web.
With Internet Explorer, the only practical way to dispense entirely with HTML
when you display XML is to attach a cascading style sheet to the XML docu-
ment and then open the document directly in the browser. However, using a cas-
cading style sheet is a relatively restrictive method for displaying and working
with XML. All the other methods you’ll learn in this book involve HTML. Data
binding and XML DOM scripts both use HTML Web pages as vehicles for dis-
playing XML documents. And with XSLT style sheets, you create templates that
transform the XML document into HTML that tells the browser how to format
and display the XML data.
Rather than replacing HTML, XML is currently used in conjunction with
HTML and vastly extends the capability of Web pages to:
I Deliver virtually any type of document
I Sort, filter, rearrange, find, and manipulate the information in
other ways
I Present highly structured information
As the quotation at the beginning of the chapter states, XML was designed for
interoperability with HTML.

What is XML ?

ma.vinothkumar — Thu, 12 Nov 2009 12:24:37 +0000

XML stands for Extensible Markup Language, was defined by the
XML Working Group of the World Wide Web Consortium (W3C). This group
described the language as follows:
The Extensible Markup Language (XML) is a subset of SGML…Its
goal is to enable generic SGML to be served, received, and processed
on the Web in the way that is now possible with HTML. XML has been
designed for ease of implementation and for interoperability with both
SGML and HTML.

As you can see, XML is a markup language designed specifically for delivering
information over the World Wide Web, just like HTML (Hypertext Markup
Language), which has been the standard language used to create Web pages
since the inception of the Web. Since we already have HTML, which continues
to evolve to meet additional needs, you might wonder why we require a com-
pletely new language for the Web.