|
Writing XHTML demands a clean HTML syntax.
Some More XHTML Syntax Rules:
- Attribute names must be in lower case
- Attribute values must be quoted
- Attribute minimization is forbidden
- The id attribute replaces the name attribute
- The XHTML DTD defines mandatory elements
Attribute Names Must Be In Lower Case
This is wrong:
This is correct:
Attribute Values Must Be Quoted
This is wrong:
This is correct:
Attribute Minimization Is Forbidden
This is wrong:
<input checked>
<input readonly>
<input disabled>
<option selected>
<frame noresize>
|
This is correct:
<input checked="checked" />
<input readonly="readonly" />
<input disabled="disabled" />
<option selected="selected" />
<frame noresize="noresize" />
|
Here is a list of the minimized attributes in HTML and how
they should be written in XHTML:
| HTML |
XHTML |
| compact |
compact="compact" |
| checked |
checked="checked" |
| declare |
declare="declare" |
| readonly |
readonly="readonly" |
| disabled |
disabled="disabled" |
| selected |
selected="selected" |
| defer |
defer="defer" |
| ismap |
ismap="ismap" |
| nohref |
nohref="nohref" |
| noshade |
noshade="noshade" |
| nowrap |
nowrap="nowrap" |
| multiple |
multiple="multiple" |
| noresize |
noresize="noresize" |
The id Attribute Replaces The name Attribute
HTML 4.01 defines a name attribute for the elements a,
applet, frame, iframe, img, and map. In XHTML the name attribute
is deprecated. Use id instead.
This is wrong:
<img src="picture.gif" name="picture1" />
|
This is correct:
<img src="picture.gif" id="picture1" />
|
Note: To interoperate with older browsers for a while,
you should use both name and id, with identical attribute
values, like this:
<img src="picture.gif" id="picture1" name="picture1" />
|
IMPORTANT Compatibility Note:
To make your XHTML compatible with today's browsers, you
should add an extra space before the "/" symbol.
The Lang Attribute
The lang attribute applies to almost every XHTML element. It
specifies the language of the content within an element.
If you use the lang attribute in an element, you must add the
xml:lang attribute, like this:
<div lang="no" xml:lang="no">Heia Norge!</div>
|
Mandatory XHTML Elements
All XHTML documents must have a DOCTYPE declaration. The
html, head and body elements must be present, and the title must
be present inside the head element.
This is a minimum XHTML document template:
<!DOCTYPE Doctype goes here>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Title goes here</title>
</head>
<body>
Body text goes here
</body>
</html>
|
Note: The DOCTYPE declaration is not a part of the
XHTML document itself. It is not an XHTML element, and it should
not have a closing tag.
Note: The xmlns attribute inside the <html> tag is
required in XHTML. However, the validator on w3.org does not
complain when this attribute is missing in an XHTML document.
This is because "xmlns=http://www.w3.org/1999/xhtml" is a fixed
value and will be added to the <html> tag even if you do not
include it.
You will learn more about the XHTML document type definition
in the next chapter |
