What is the benefit to add css code in comment?
<STYLE type="text/css">
<!--
H1 { color: red }
P { color: blue}
-->
</STYLE>
Should we use this always or no need? Is it same like CDATA for javascript?
views:
70answers:
4
+2
A:
This is done for backwards compatibility with rendering engines that do not understand the style tag. By placing your styles in a comment, the engine will (hopefully) not render them as plain text.
This practice is less important now that the majority of clients can render styles properly, but it is still somewhat common to see. I generally neglect it in my own code, but that's personal preference.
Joel Potter
2010-01-08 03:07:53
it means in that browser user will see plain html page , no css
metal-gear-solid
2010-01-08 03:09:14
No. Rather, if the browser doesn't know what to do with a `style` tag, it will prevent the browser from showing the rules to the user.
Joel Potter
2010-01-08 03:12:34
if the browser doesn't know what to do with a style tag, will user see plain HTML page?
metal-gear-solid
2010-01-08 03:14:06
Yes... if the user manages to see an HTML page at all, since to find a browser that didn't know about script and style tags you'd have to go back many, many years, to before browsers supported HTTP 1.1 (good luck talking to half today's web servers without the Host header!). There are (somewhat) up-to-date browsers that don't *support* CSS or JavaScript, but they still know that the tags exist, so they don't render the contents, and don't need the comment-hiding.
bobince
2010-01-08 05:28:33
+1
A:
You should always include your styles in external stylesheets whenever possible. When you have to include them on the page, it more common to see the contents wrapped in <!CDATA[[ ... ]]> blocks than comments.
The comments will not disable the rules in any modern browsers.
Doug Neiner
2010-01-08 03:11:14
BalusC
2010-01-08 03:17:38
A:
In Dreamweaver (DW), it's very 'convenient' to change the page's doctype declaration.
If XHTML is used, <!-- .... --> or<!CDATA[[ ... ]]> will kick in to enable strict parsing and compliance.
In any case, it is backward compatible (almost) with other doctype declarations, it make sense for DW to always use this convention.
o.k.w
2010-01-08 03:17:52
is <!-- .... --> and <!CDATA[[ ... ]]> works same for XHTML document, for in-page Javascript and CSS both?
metal-gear-solid
2010-01-08 03:22:46
Well, I don't think they will be 100% the same for JS and CSS but pretty much I guess.
o.k.w
2010-01-08 03:31:26
so it's better to use <!-- .... --> for css and <!CDATA[[ ... ]]> for javascript always in XHTML document.
metal-gear-solid
2010-01-08 03:55:54
Like what BalusC commented in one of the posts on this question, unless your enclosed content contains "XML-illegal" characters, using `<!-- ... -->` should suffice. Older browsers might not recognise what is CDATA.
o.k.w
2010-01-08 04:28:24
+4
A:
It's archaic cruft meant to support HTML 2.0 browsers from 15-odd years ago. Those browsers didn't know about the <script> and <style> tags, so unless the content inside them was hidden inside comment markup, it would spit them out onto the page as text content, causing a nasty mess.
There is absolutely no purpose to the practice today, but still it hangs on, thanks to cut-and-paste coding and poor authoring tools like Dreamweaver.
In XHTML served as XML you must not include the comment markup, otherwise your script or stylesheet really is only a comment and will be completely ignored.
Some authors use a <![CDATA[ ... ]]> section for scripts and stylesheets in XHTML, but this is for a completely different reason. It allows you to include a literal < or & character inside the content without having to do the correct XML thing and escape it to < or &. Apart from making code harder to read, an HTML-escape in scripts and styles would confuse legacy non-XML HTML parsers: in HTML4, the script and style elements are magic and can have those characters in without escaping (the one sequence you can't use is </ since that ends the element).
When you do use a CDATA section in a document you intend to be read by non-XML HTML parsers, you should use a CSS or JavaScript comment to hide the CDATA section markup:
<script type="text/javascript">//<![CDATA[
...
//]]></script>
<style type="text/css">/* <![CDATA[ */
...
/* ]]> */</style>
For the old-school comment-wrapping common in HTML 3.2, an exception was made to CSS and JS parsing to allow <!-- and --> sequences to slip through unnoticed, but this is not the case for <![CDATA[ or ]]> which would be seen by a CSS or JavaScript parser as a syntax error.
If, heaven forbid, you needed to support HTML 2.0, 3.2+ and XHTML parsers, you'd end up needing this hideous mess:
<script type="text/javascript"><!--//--><![CDATA[//><!--
...
//--><!]]></script>
<style type="text/css"><!--/*--><![CDATA[/*><!--*/
...
/*]]>*/--></style>
thankfully this is never going to happen.
You can usually get away with no comment or CDATA cruft at all, since CSS almost never needs to use the < or & characters, and in JavaScript you can usually recast less-than comparisons as harmless >, and logical-ands to inverted logical-ors. Both CSS and JavaScript offer native escapes for when you want to put a < or & character in a string literal (eg. '\x3C').
In any case, significant amounts of style and script — where you're most likely to want to use those characters — should generally be in an external linked file, making the point moot.
bobince
2010-01-08 05:09:25