Versions of HTML
HTML 1.0 -->> HTML 2.0-->>HTML 3.0 -->> HTML 3.2 -->> HTML 4.0 -->>HTML 4.01-->>XHTML 1.0
What is DTD ?
A DTD in an XML or HTML document provides a list of the elements, attributes, comments, notes, and entities contained in the document. It also indicates their relationship to one another within the document. In other words, a DTD is the grammar of an XML or HTML document.
Purpose of a DTD
When using a DTD for an XML document (including XHTML), the DTD is there to provide structure for your documents. It is easy to write an XML document, but without the DTD, it has no syntactic meaning to the computer. For example, if you come across this portion of an XML document:
"<"address">"
"<"street">"123 Any Street"<"/street">"
"<"city">"Giridar"<"/city">" "<"state">"AP"<"/state">"
"<"/address">"
While you would know it was an address, you wouldn't know whether it was an address the computer was supposed to create from a database table, if that address was for mailing, and other things. The computer, on the other hand, wouldn't see this as anything more than a string of text. If you viewed it in an XML browser, you might not get any errors, but you also wouldn't get a very interesting or useful page.
In other articles, we'll explore the inner workings of a DTD, and examine the elements that make up a DTD. You'll learn what an element, attribute, entity, and notation is and how to use them within your own DTDs. Plus, you'll learn how to read other DTDs so that you can use them in your own XML documents.
Using DIV Tag
"<"div">" Description:
The "<"div">" element defines logical divisions within the document. This means that when you use a "<"div">" element, you are indicating that the enclosed content is a specific section of the page. The "<"div">" element is typically used in XHTML+CSS documents to position portions of the page.
The "<"div">" tag is a block-level element.
"<"div">" Web Browser Support:
• Netscape 2, 3, 4, 6, 7
• Mozilla 1
• Firefox 1
• Internet Explorer 3, 4, 5, 6
• Opera 3, 4, 5, 6, 7, 8
• Safari 1
• WebTV/MSN TV
• AvantGo Palm OS
• AvantGo Windows CE
• HTML 4.0
• XHTML 1.0: XHTML Text Module

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