These are non-HTML tags and markers used in HTML documents
| The DOCTYPE |
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The DOCTYPE declaration is an XML tag, and
is the required first element of an HTML file. Copy one of the following as the first element of your webpage: |
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
Strict:
use when the document complies with all current standards.
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
Transitional:
use when the document contains disapproved (or, "deprecated") HTML tags,
in an attempt to make the web page "backward-compatible" with outdated
browsers.
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
Frameset:
use when the web page has an outdated "frames" structure, in which a
patchwork of separate html files are combined to display all at once.
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| Comment Markers | |
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<!-- Data typed between
comment markers doesn't show up on the web page -->
These comment markers are commonly
used to write notes to yourself that won't show up in the browser window -- they only
show up in the source document. The comment itself may span multiple lines, and may
include virtually any characters except a double dash (
-- ).
Unfortunately, these markers have been widely used in style and script elements (in the head of the file) for the sake of older browsers, as previously recommended by W3C. But newer XML display processing is allowed to delete anything between comment markers, including style and script instructions. A better solution than trying to "hide" these codes from older browsers is to use external documents for style sheets and scripts. |
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| Style Sheet and Script Comment Markers | |
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/* Use
these comment markers in style sheets and scripts. */
These comment markers are
used around notes in both internal and external style sheets,
and in scripts.
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| Script Comment Markers | |
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// Use
this comment marker in script elements.
Double slashes form a script
comment marker, used either at the end of a line within the script,
or beginning a new line of its own.
The comment cannot contain a line break because there is no end marker.
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| CDATA Markers | |
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<![CDATA[ the script goes here
]]>
Character data markers are used to contain
programming scripts that standard XML processing might otherwise misinterpret.
In addition to the script element, the style element (for
internal style sheets) is defined as having CDATA
content. [Since CSS doesn't use any of the conflicting XML punctuation,
this marker seems unnecessary in internal style sheets.]
Current browsers don't always understand
the CDATA marker, so it's better to use external documents
for both JavaScript and style sheets.
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