Editing Help:HTML in wikitext

{{H:h|editor toc}}

==Permitted HTML==
The following [[w:HTML element|HTML element]]s are permitted in the latest version of MediaWiki software:
        
{| border="0" cellpadding="5"
| valign="top"|
* [[w:HTML element#abbr|&lt;abbr&gt;]]
* [[w:HTML element#b|&lt;b&gt;]]
* [[w:HTML element#bdi|&lt;bdi&gt;]]
* [[w:HTML element#big|&lt;big&gt;]]
* [[w:HTML element#blockquote|&lt;blockquote&gt;]]
* [[w:HTML element#br|&lt;br&gt;]]
* [[w:HTML element#caption|&lt;caption&gt;]]
* [[w:HTML element#center|&lt;center&gt;]]
* [[w:HTML element#cite|&lt;cite&gt;]]
* [[w:HTML element#code|&lt;code&gt;]]
* [[w:HTML element#dd|&lt;dd&gt;]]
* [[w:HTML element#del|&lt;del&gt;]]
* [[w:HTML element#dfn|&lt;dfn&gt;]]
* [[w:HTML element#div|&lt;div&gt;]]
* [[w:HTML element#dl|&lt;dl&gt;]]
* [[w:HTML element#dt|&lt;dt&gt;]]
* [[w:HTML element#em|&lt;em&gt;]]
* [[w:HTML element#font|&lt;font&gt;]]
| valign="top"|
* [[w:HTML element#h1|&lt;h1&gt;]]
* [[w:HTML element#h2|&lt;h2&gt;]]
* [[w:HTML element#h3|&lt;h3&gt;]]
* [[w:HTML element#h4|&lt;h4&gt;]]
* [[w:HTML element#h5|&lt;h5&gt;]]
* [[w:HTML element#h6|&lt;h6&gt;]]
* [[w:HTML element#hr|&lt;hr&gt;]]
* [[w:HTML element#i|&lt;i&gt;]]
* [[w:HTML element#ins|&lt;ins&gt;]]
* [[w:HTML element#kbd|&lt;kbd&gt;]]
* [[w:HTML element#li|&lt;li&gt;]]
* [[w:HTML element#ol|&lt;ol&gt;]]
* [[w:HTML element#p|&lt;p&gt;]]
* [[w:HTML element#pre|&lt;pre&gt;]]
* [http://www.w3.org/TR/1999/WD-ruby-19990322/ &lt;rb&gt;]
* [http://www.w3.org/TR/1999/WD-ruby-19990322/ &lt;rp&gt;]
* [http://www.w3.org/TR/1999/WD-ruby-19990322/ &lt;rt&gt;]
* [http://www.w3.org/TR/1999/WD-ruby-19990322/ &lt;ruby&gt;]
| valign="top"|
* [[w:HTML element#s|&lt;s&gt;]]
* [[w:HTML element#samp|&lt;samp&gt;]]
* [[w:HTML element#small|&lt;small&gt;]]
* [[w:HTML element#span|&lt;span&gt;]]
* [[w:HTML element#strike|&lt;strike&gt;]]
* [[w:HTML element#strong|&lt;strong&gt;]]
* [[w:HTML element#sub|&lt;sub&gt;]]
* [[w:HTML element#sup|&lt;sup&gt;]]
* [[w:HTML element#table|&lt;table&gt;]]
* [[w:HTML element#td|&lt;td&gt;]]
* [[w:HTML element#th|&lt;th&gt;]]
* [[w:HTML element#tr|&lt;tr&gt;]]
* [[w:HTML element#tt|&lt;tt&gt;]]
* [[w:HTML element#u|&lt;u&gt;]]
* [[w:HTML element#ul|&lt;ul&gt;]]
* [[w:HTML element#var|&lt;var&gt;]]
* [[w:HTML element#Comments|&lt;!-- ... --&gt;]]
|}


For many HTML elements, more convenient wikitext code is available, see [[Help:Editing]]. On the other hand, HTML tags allow an <tt>id</tt> that can be referenced in one's [[Help:User style|user style]] css, and allows the tag to be used as link target.


For example, the anchor element <tt><a></tt> is not allowed, so the wikitext

: <code><nowiki><a href="http://meta.wikimedia.org/">Main Page</a></nowiki></code>

is treated like the wikitext

: <code><nowiki>&amp;lt;a href="http://meta.wikimedia.org/"&amp;gt;Main Page&amp;lt;/a&amp;gt;</nowiki></code>

and is therefore displayed as

: <nowiki><a href="http://meta.wikimedia.org/">Main Page</a></nowiki>

which is unlikely to be what the editor intended. Instead of using the anchor element (&lt;a&gt;) the wiki markup for external reference is recommended (enclosed in square brackets with the URL separated from the contents by a single space):

: <code><nowiki>[http://meta.wikimedia.org/ Main Page]</nowiki></code>

displays as:

: [http://meta.wikimedia.org/ Main Page]


<br clear=all><!-- stop floating navbox before pre -->

The following excerpt from [https://gerrit.wikimedia.org/r/gitweb?p=mediawiki/core.git;a=blob;f=includes/Sanitizer.php;hb=HEAD Sanitizer.php] additionally shows which attributes are allowed.

<source lang=php>
            $htmlpairsStatic = array( # Tags that must be closed
                'b', 'bdi', 'del', 'i', 'ins', 'u', 'font', 'big', 'small', 'sub', 'sup', 'h1',
                'h2', 'h3', 'h4', 'h5', 'h6', 'cite', 'code', 'em', 's',
                'strike', 'strong', 'tt', 'var', 'div', 'center',
                'blockquote', 'ol', 'ul', 'dl', 'table', 'caption', 'pre',
                'ruby', 'rt', 'rb', 'rp', 'p', 'span', 'abbr', 'dfn',
                'kbd', 'samp', 'data', 'time', 'mark'
            );
            $htmlsingle = array(
                'br', 'hr', 'li', 'dt', 'dd'
            );
            $htmlsingleonly = array( # Elements that cannot have close tags
                'br', 'hr'
            );
            $htmlnest = array( # Tags that can be nested--??
                'table', 'tr', 'td', 'th', 'div', 'blockquote', 'ol', 'ul',
                'li', 'dl', 'dt', 'dd', 'font', 'big', 'small', 'sub', 'sup', 'span',
                'var', 'kbd', 'samp'
            );
            $tabletags = array( # Can only appear inside table, we will close them
                'td', 'th', 'tr',
            );
            $htmllist = array( # Tags used by list
                'ul', 'ol',
            );
            $listtags = array( # Tags that can appear in a list
                'li',
            );
</source>

== Tags ==

{{mlw|HTML_element|Span|<code>'''&lt;span>'''</code>}} is a generic inline text container. 

<code>'''&lt;font>'''</code> is a similar tag which is [[w:Deprecation|deprecate]]d (should not be used) in favor of <nowiki><span></nowiki>.''

For example
<source lang=html4strict>
a <font color="red">red</font> word.
</source>
produces the same result as
<source lang=html4strict>
a <span style="color:red">red</span> word.
</source>

See also {{tim|font size demo}} and {{mlm|Help:Text color}}.

It's pointless to combine the legacy tag <tt>&lt;font&gt;</tt>
with inline CSS; legacy browsers would ignore the CSS, while
modern browsers support <tt>&lt;span&gt;</tt> (see above).

Note that in most cases, one can use a more descriptive tag, for instance, <strong><nowiki><strong></nowiki></strong> to indicate an important piece of text, or <em><nowiki><em></nowiki></em> (subject to the same things as strong) to indicate an emphasized piece of text. 

This not only draws the user's attention to the text, but can also alert those who are using nonvisual browsers or have sight impairments, etc. to the fact that that is <em>emphasized text</em>.

===Using <nowiki><span></nowiki> as a link target===

The standard way of providing a named anchor as an invisible target (i.e. <code><a name="Foo"></code>) doesn't work (since all <code><a></code> tags are converted), and [http://www.w3.org/TR/html401/struct/links.html an alternative suggested by the W3C], <code><nowiki><hN id="Foo"></hN></nowiki></code>, produces an "[Edit]" link.

However, <code><nowiki><span id="Foo"></nowiki></code> does produce a target that can be the destination of a link. Note that it doesn't work everywhere; for instance, in a table, it has to be inside a cell before some browsers will jump to it properly.

===<nowiki><div></nowiki>===
<code>'''&lt;div>'''</code> is a generic block container. Rules:
* <nowiki><div></nowiki> should be followed by a newline
* <nowiki></div></nowiki> should be preceded by a newline
*<nowiki></div></nowiki> followed by text on the same line, two newlines and text before <nowiki><div></nowiki> on the same line should be avoided (because the two newlines only produce a space)

Example:

{{xpdplain|
--|--|
|o

p<|div>q<|/div>r

s<|div>|t|
|u|
|v|
|x<|/div>y

s<|div>|t|
|u|
|v|
|x<|/div>y

z|
|--|--|
}}

===HTML comment===
Using {{tim|t}}:
*{{xpd|t}}
*"<code><nowiki>{{subst:xpd|t}}</nowiki>"</code> gives the wikitext "<code>&lt;!--t-->start-pqr-end"<code>, producing HTML code without the comment.
The "Remove comments" option of [[mw:Extension:ExpandTemplates|ExpandTemplates]] selects whether comments are removed, not just in the final result but throughout the expansion process. This affects the result of parser functions: a comment in the expression of #expr or in the condition of #ifexpr gives an error message unless "Remove comments" is on, and comments affect #if and ifeq.

Example:

Wikitext:
----
<pre>
{{#expr:<!--p-->3}}

{{#ifeq:<!--p-->3|3|1|0}}

{{#if:<!--p-->|1|0}}
</pre>
----
Result of normal expansion, and of ExpandTemplates with "Remove comments" on:
----
{{#expr:<!--p-->3}}

{{#ifeq:<!--p-->3|3|1|0}}

{{#if:<!--p-->|1|0}}
----
Result of full substitution, and of ExpandTemplates with "Remove comments" off:
----
<strong class="error">Expression error: Unrecognised punctuation character ""</strong>

0

1
----
Therefore it is typically better to avoid comments in these places, and to put the comment before or after the parser function.

In the case of nested parser functions, to avoid having to put the comments outside the whole, an alternative is <nowiki>{{void|</nowiki>''comment''}}. In the case of substitution of the parser function, "void" has to be substituted too, e.g. in a template allowing multi-level substitution we can put <nowiki>{{{{{subst1|}}}#expr:3*{{{1}}} {{{{{subst1|}}}void|</nowiki> multiply by 3 }}}}.

Another alternative is making the comment the name of a parameter (in the likely case that it is unused), with the empty string as default, e.g. <nowiki>{{{ multiply by 3 |}}} or, to recognize the intention, use pseudo comment tags: {{{<!- multiply by 3 ->|}}}, or real ones, if the empty string is not used as parameter: {{{<!-- multiply by 3 -->|}}}</nowiki>.

See also {{tim|t comment}}.

== Attributes ==

Most tags can have a <tt>style</tt> attribute. For example 
<source lang=html4strict>
<div style="font-size:80%">
This is <span style="color:red">red</span> text.
</div>
</source>
produces:
<blockquote style="border:1px dotted gray; padding-left:20px">
<div style="font-size:80%">
This is <span style="color:red">red</span> text.
</div>
</blockquote>


Most tags can have classes and IDs. They can be used in conjunction with stylesheets to give a piece of text a descriptive class (or unique identifier) and to refer to that in a stylesheet.
For example

<source lang=html4strict>
<div class="infobox">Example infobox</div>
</source>

<div class="infobox">Example infobox</div>
Produces the box which floats on the right because <tt>infobox</tt> class is already defined in local [[Mediawiki:Common.css]].
<br style=clear:all>

Classes and IDs can also be used by Javascript code, for example see [[:en:Template_talk:Link_FA#How_does_it_work.3F|how {Link FA} works]] in enwiki.


Another attribute example is <tt>title</tt>, for example used in {{tl|H:title}} template: note the hover box over "20000 ft"
<blockquote style="border:1px dotted gray; padding-left:20px">
"a height of {{h:title|6.1 km|20000 ft}} above sea level"
</blockquote>

<!--
This is suitable if the color is specifically intended to be red; if it is just for emphasis a more general term for the class would be more appropriate, because css allows the user to choose another method of emphasis (another color, bold, enlarged, etc.).

Note that many readers will not have their own css with such lines as ".red {color:red}", so one cannot refer to "the red text above", etc.
-->

== Tags with special effect ==
=== Pre ===
<nowiki><pre></nowiki> tags work as the combination of <nowiki><nowiki></nowiki> and the standard HTML <nowiki><pre></nowiki> tag: the content will preformatted, and it will not be parsed, but shown as in the wikitext source. If you want preformatted but parsed text, use a space in the beginning of the line instead. For example,

 <nowiki><pre>This word is <b>bold</b>.</pre>
  This word is <b>bold</b>.</nowiki>
will render as

<pre>This word is <b>bold</b>.</pre>
 This word is <b>bold</b>.

=== Comments ===
HTML comments in the wikitext (<nowiki><!-- ... --></nowiki>) will not appear in the HTML code at all.

=== Headers ===
Headers (<nowiki><h1>...<h6></nowiki>) will be treated in a similar way as wikicode headers:

<h6>sample header</h6>

Note that it appears in the table of contents and has an accompanying edit link. There are some minor differences though: editing such a section won't prefill the edit summary, and the browser won't jump to the beginning of the section when saving the page. Thus, you should use the wikitext equivalents instead.

== Exceptions ==
In some pages in the MediaWiki namespace (typically the short messages like button labels) HTML does not work, and e.g. &lt;span id=abc&gt; produces the HTML &amp;lt;span id=abc&amp;gt; rendered by the browser as &lt;span id=abc&gt;. Some others are interpreted as pure HTML (thus any tag can be used, but wikicode won't be transformed to HTML).

User CSS and JS pages (see [[Help:User style]]) are interpreted as if inside a <nowiki><pre></nowiki> block. From MW 1.11 this also goes for sitewide CSS/JS; in earlier versions, you have to manually add <tt><nowiki>/*<pre>*/</nowiki></tt> to the beginning and <tt><nowiki>/*</pre>*/</nowiki></tt> to the end of those pages to avoid strange rendering.

== External links ==
* HTML 4.01 specification: [http://www.w3.org/TR/html401/index/elements.html elements] | [http://www.w3.org/TR/html401/index/attributes.html attributes]
* For customizing the handling of HTML in MediaWiki, see the HTML and Tidy sections in [[mw:Manual:Configuration settings]]
* Some extensions allow adding arbitrary HTML to a page, for example [[mw:Extension:AddHTML]],[[mw:Extension:SecureHTML]] and [[mw:Extension:Secure HTML]]; see [http://www.mediawiki.org/wiki/Manual:%24wgRawHtml $wgRawHtml] for a more complete list
* Within the MediaWiki codebase, these HTML checks happen in [https://gerrit.wikimedia.org/r/gitweb?p=mediawiki/core.git;a=blob;f=includes/Sanitizer.php;hb=HEAD includes/Sanitizer.php]

{{H:f|langs=|enname=HTML in wikitext}}

[[Category:Editor handbook]]