XHTML - vs HTML
XHTML is not very different from the HTML 4.01 standard.
So, bringing your code up to the 4.01 standard is a good start.
Our complete
HTML 4.01 reference can help you with that.
In addition, you should start NOW to write your HTML code in lowercase letters, and NEVER skip closing tags (like </p>).
- XHTML elements must be properly nested
- XHTML elements must always be closed
- XHTML elements must be in lowercase
- XHTML documents must have one root element
In HTML, some elements can be improperly nested within each other, like this:
<b><i>This text is bold and italic</b></i>
In XHTML, all elements must be properly nested within each other, like this:
<b><i>This text is bold and italic</i></b>
Note: A common mistake with nested lists, is to forget that the inside list must be within <li> and </li> tags.
This is wrong:
<ul>
<li>Coffee</li>
<li>Tea
<ul>
<li>Black tea</li>
<li>Green tea</li>
</ul>
<li>Milk</li>
</ul>
This is correct:
<ul>
<li>Coffee</li>
<li>Tea
<ul>
<li>Black tea</li>
<li>Green tea</li>
</ul>
</li>
<li>Milk</li>
</ul>
Notice that we have inserted a </li> tag after the </ul> tag in the "correct" code example.
Non-empty elements must have a closing tag.
This is wrong:
<p>This is a paragraph
<p>This is another paragraph
This is correct:
<p>This is a paragraph</p>
<p>This is another paragraph</p>
Empty elements must also be closed.
This is wrong:
A break: <br>
A horizontal rule: <hr>
An image: <img src="happy.gif" alt="Happy face">
This is correct:
A break: <br />
A horizontal rule: <hr />
An image: <img src="happy.gif" alt="Happy face" />
Tag names and attributes must be in lower case.
This is wrong:
<BODY>
<P>This is a paragraph</P>
</BODY>
This is correct:
<body>
<p>This is a paragraph</p>
</body>
All XHTML elements must be nested within the root element.
Child elements must be in pairs and correctly nested within their parent element.
The basic document structure is:
<html>
<head> ... </head>
<body> ... </body>
</html>
