What is XHTML?
XHTML (eXtensible HyperText Markup Language) is nothing but just HTML 4.01 with restrictions on following the standard. While writing a XHTML document we have to follow all the rules and standards.
Why XHTML?
The main reason behind XHTML is to maintain the same coding standard among all the web sites so that web pages render properly in all the web browsers. XHTML is a cleaner version of HTML4.01. A document written using XHTML can be rendered properly by all the web browsers. if you already know HTML then it will take just 10 minutes to learn XHTML. Just follow the rules give below and enjoy your XHTML programming.
XHTML rules
Rule 1. All the tags must be closed, even empty elements
| Wrong | Right |
|---|---|
|
<div> <span>Home Page <br> |
<div> <span>Home Page</span> <br/> </div> |
Rule 2. All the tags and attributes should be written in lower case.
| Wrong | Right |
|---|---|
|
<HTML> <HEAD> <TITLE>Home Page</TITLE> </HEAD> <BODY> </BODY> </HTML> |
<html> <head> <title>Home Page</title> </head> <body> </body> </html> |
Rule 3. All the tags should be properly nested
| Wrong | Right |
|---|---|
|
<b><i>Hello World</b></i> |
<b><i>Hello World</i></b> |
Rule 4. Image (img) tag should contain 'alt' attribute.
| Wrong | Right |
|---|---|
|
<img src="image1.jpeg"/> |
<img src="image1.jpeg" alt="Image 1"/> |
Rule 5. Specify "type" attribute in <script> and <style> tags.
| Wrong | Right |
|---|---|
|
<style> </style>
<script> </script> |
<style type="text/css"> </style>
<script type="text/javascript"> </script> |
Rule 6. <style> tags should only be declared in <head></head> section.
| Wrong | Right |
|---|---|
|
<body> <style> </style> </body> |
<head> <style> </style> </head> |
Rule 7. Attrubute values must be quoted
| Wrong | Right |
|---|---|
|
<div width=500px></div> |
<div width="500px"></div> |
Rule 8. Attrubutes can't be minimized
| Wrong | Right |
|---|---|
|
<input type="checkbox" name="chk1" checked /> |
<input type="checkbox" name="chk1" checked="checked" /> |
