Basic HTML tags

Here we analyze, which types of HTML tags are allowed inside the content field. Sanitizing fields is desired behavior as seen in Section B.10 of ActivityPub.

The ✅ means that the html tag was left unchanged. ❓ indicates the content was changed, by hovering over it, one can see into what.

❓ for misskey is due us not supporting checking markdown yet.

Support table

content	akkoma	friendica	gotosocial	hollo	mastodon	misskey	mitra	pleroma	sharkey
<b>bold</b>	✅	✅	✅	✅	✅	❓	✅	✅	❓
<strong>strong</strong>	✅	✅	✅	✅	✅	❓	✅	✅	❓
<i>italic</i>	✅	✅	✅	✅	✅	❓	✅	✅	❓
<em>emphasis</em>	✅	✅	✅	✅	✅	❓	✅	✅	❓
<s>stricken</s>	❓	✅	✅	✅	✅	❓	✅	✅	❓
<ol><li>ordered</li></ol>	✅	✅	✅	✅	✅	❓	✅	✅	❓
<ul><li>unordered</li></ul>	✅	✅	✅	✅	✅	❓	✅	✅	❓
<h1>h1</h1>	❓	✅	✅	✅	❓	❓	✅	❓	❓
<h2>h2</h2>	❓	✅	✅	✅	❓	❓	✅	❓	❓
<h3>h3</h3>	❓	✅	✅	✅	❓	❓	✅	❓	❓
<h4>h4</h4>	❓	✅	✅	✅	❓	❓	✅	❓	❓
<h5>h5</h5>	❓	✅	✅	✅	❓	❓	✅	❓	❓
<code>code</code>	✅	✅	✅	✅	✅	❓	✅	✅	❓
<pre>pre</pre>	✅	❓	✅	✅	✅	❓	✅	✅	❓
<blockquote>blockquote</blockquote>	✅	✅	✅	✅	✅	❓	✅	✅	❓
line<br>break	❓	✅	✅	✅	✅	❓	✅	❓	❓
<p>paragraph</p>	✅	❓	✅	✅	✅	❓	✅	✅	✅
<small>small</small>	✅	❓	✅	✅	❓	❓	✅	✅	❓
<sup>sup</sup>	✅	✅	✅	✅	❓	❓	✅	✅	❓
<sub>sub</sub>	✅	✅	✅	✅	❓	❓	✅	✅	❓

Details

akkomafriendicagotosocialhollomastodonmisskeymitrapleromasharkey

content	content	Example
<b>bold</b>	<b>bold</b>
<strong>strong</strong>	<strong>strong</strong>
<i>italic</i>	<i>italic</i>
<em>emphasis</em>	<em>emphasis</em>
<s>stricken</s>	stricken
<ol><li>ordered</li></ol>	<ol><li>ordered</li></ol>
<ul><li>unordered</li></ul>	<ul><li>unordered</li></ul>
<h1>h1</h1>	h1
<h2>h2</h2>	h2
<h3>h3</h3>	h3
<h4>h4</h4>	h4
<h5>h5</h5>	h5
<code>code</code>	<code>code</code>
<pre>pre</pre>	<pre>pre</pre>
<blockquote>blockquote</blockquote>	<blockquote>blockquote</blockquote>
line<br>break	line<br/>break
<p>paragraph</p>	<p>paragraph</p>
<small>small</small>	<small>small</small>
<sup>sup</sup>	<sup>sup</sup>
<sub>sub</sub>	<sub>sub</sub>

content	content	Example
<b>bold</b>	<b>bold</b>
<strong>strong</strong>	<strong>strong</strong>
<i>italic</i>	<i>italic</i>
<em>emphasis</em>	<em>emphasis</em>
<s>stricken</s>	<s>stricken</s>
<ol><li>ordered</li></ol>	<ol><li>ordered</li></ol>
<ul><li>unordered</li></ul>	<ul><li>unordered</li></ul>
<h1>h1</h1>	<h1>h1</h1>
<h2>h2</h2>	<h2>h2</h2>
<h3>h3</h3>	<h3>h3</h3>
<h4>h4</h4>	<h4>h4</h4>
<h5>h5</h5>	<h5>h5</h5>
<code>code</code>	<code>code</code>
<pre>pre</pre>	pre
<blockquote>blockquote</blockquote>	<blockquote>blockquote</blockquote>
line<br>break	line<br>break
<p>paragraph</p>	paragraph
<small>small</small>	<span style="font-size:small;line-height:normal;">small</span>
<sup>sup</sup>	<sup>sup</sup>
<sub>sub</sub>	<sub>sub</sub>

content	content	Example
<b>bold</b>	<b>bold</b>
<strong>strong</strong>	<strong>strong</strong>
<i>italic</i>	<i>italic</i>
<em>emphasis</em>	<em>emphasis</em>
<s>stricken</s>	<s>stricken</s>
<ol><li>ordered</li></ol>	<ol><li>ordered</li></ol>
<ul><li>unordered</li></ul>	<ul><li>unordered</li></ul>
<h1>h1</h1>	<h1>h1</h1>
<h2>h2</h2>	<h2>h2</h2>
<h3>h3</h3>	<h3>h3</h3>
<h4>h4</h4>	<h4>h4</h4>
<h5>h5</h5>	<h5>h5</h5>
<code>code</code>	<code>code</code>
<pre>pre</pre>	<pre>pre</pre>
<blockquote>blockquote</blockquote>	<blockquote>blockquote</blockquote>
line<br>break	line<br>break
<p>paragraph</p>	<p>paragraph</p>
<small>small</small>	<small>small</small>
<sup>sup</sup>	<sup>sup</sup>
<sub>sub</sub>	<sub>sub</sub>

content	content	Example
<b>bold</b>	<b>bold</b>
<strong>strong</strong>	<strong>strong</strong>
<i>italic</i>	<i>italic</i>
<em>emphasis</em>	<em>emphasis</em>
<s>stricken</s>	<s>stricken</s>
<ol><li>ordered</li></ol>	<ol><li>ordered</li></ol>
<ul><li>unordered</li></ul>	<ul><li>unordered</li></ul>
<h1>h1</h1>	<h1>h1</h1>
<h2>h2</h2>	<h2>h2</h2>
<h3>h3</h3>	<h3>h3</h3>
<h4>h4</h4>	<h4>h4</h4>
<h5>h5</h5>	<h5>h5</h5>
<code>code</code>	<code>code</code>
<pre>pre</pre>	<pre>pre</pre>
<blockquote>blockquote</blockquote>	<blockquote>blockquote</blockquote>
line<br>break	line<br>break
<p>paragraph</p>	<p>paragraph</p>
<small>small</small>	<small>small</small>
<sup>sup</sup>	<sup>sup</sup>
<sub>sub</sub>	<sub>sub</sub>

content	content	Example
<b>bold</b>	<b>bold</b>
<strong>strong</strong>	<strong>strong</strong>
<i>italic</i>	<i>italic</i>
<em>emphasis</em>	<em>emphasis</em>
<s>stricken</s>	<s>stricken</s>
<ol><li>ordered</li></ol>	<ol><li>ordered</li></ol>
<ul><li>unordered</li></ul>	<ul><li>unordered</li></ul>
<h1>h1</h1>	<p><strong>h1</strong></p>
<h2>h2</h2>	<p><strong>h2</strong></p>
<h3>h3</h3>	<p><strong>h3</strong></p>
<h4>h4</h4>	<p><strong>h4</strong></p>
<h5>h5</h5>	<p><strong>h5</strong></p>
<code>code</code>	<code>code</code>
<pre>pre</pre>	<pre>pre</pre>
<blockquote>blockquote</blockquote>	<blockquote>blockquote</blockquote>
line<br>break	line<br>break
<p>paragraph</p>	<p>paragraph</p>
<small>small</small>	small
<sup>sup</sup>	sup
<sub>sub</sub>	sub

content	text	Example
<b>bold</b>	**bold**
<strong>strong</strong>	**strong**
<i>italic</i>	<i>italic</i>
<em>emphasis</em>	<i>emphasis</i>
<s>stricken</s>	~~stricken~~
<ol><li>ordered</li></ol>	ordered
<ul><li>unordered</li></ul>	unordered
<h1>h1</h1>	【h1】
<h2>h2</h2>	h2
<h3>h3</h3>	h3
<h4>h4</h4>	h4
<h5>h5</h5>	h5
<code>code</code>	`code`
<pre>pre</pre>	pre
<blockquote>blockquote</blockquote>	> blockquote
line<br>break	line break
<p>paragraph</p>	paragraph
<small>small</small>	<small>small</small>
<sup>sup</sup>	sup
<sub>sub</sub>	sub

content	content	Example
<b>bold</b>	<b>bold</b>
<strong>strong</strong>	<strong>strong</strong>
<i>italic</i>	<i>italic</i>
<em>emphasis</em>	<em>emphasis</em>
<s>stricken</s>	<s>stricken</s>
<ol><li>ordered</li></ol>	<ol><li>ordered</li></ol>
<ul><li>unordered</li></ul>	<ul><li>unordered</li></ul>
<h1>h1</h1>	<h1>h1</h1>
<h2>h2</h2>	<h2>h2</h2>
<h3>h3</h3>	<h3>h3</h3>
<h4>h4</h4>	<h4>h4</h4>
<h5>h5</h5>	<h5>h5</h5>
<code>code</code>	<code>code</code>
<pre>pre</pre>	<pre>pre</pre>
<blockquote>blockquote</blockquote>	<blockquote>blockquote</blockquote>
line<br>break	line<br>break
<p>paragraph</p>	<p>paragraph</p>
<small>small</small>	<small>small</small>
<sup>sup</sup>	<sup>sup</sup>
<sub>sub</sub>	<sub>sub</sub>

content	content	Example
<b>bold</b>	<b>bold</b>
<strong>strong</strong>	<strong>strong</strong>
<i>italic</i>	<i>italic</i>
<em>emphasis</em>	<em>emphasis</em>
<s>stricken</s>	<s>stricken</s>
<ol><li>ordered</li></ol>	<ol><li>ordered</li></ol>
<ul><li>unordered</li></ul>	<ul><li>unordered</li></ul>
<h1>h1</h1>	h1
<h2>h2</h2>	h2
<h3>h3</h3>	h3
<h4>h4</h4>	h4
<h5>h5</h5>	h5
<code>code</code>	<code>code</code>
<pre>pre</pre>	<pre>pre</pre>
<blockquote>blockquote</blockquote>	<blockquote>blockquote</blockquote>
line<br>break	line<br/>break
<p>paragraph</p>	<p>paragraph</p>
<small>small</small>	<small>small</small>
<sup>sup</sup>	<sup>sup</sup>
<sub>sub</sub>	<sub>sub</sub>

content	content	Example
<b>bold</b>	<p><span>bold</span></p>
<strong>strong</strong>	<p><span>strong</span></p>
<i>italic</i>	<p><span>italic</span></p>
<em>emphasis</em>	<p><span>emphasis</span></p>
<s>stricken</s>	<p><span>~~stricken~~</span></p>
<ol><li>ordered</li></ol>	<p>ordered</p>
<ul><li>unordered</li></ul>	<p>unordered</p>
<h1>h1</h1>	<p><span>【h1】</span></p>
<h2>h2</h2>	<p><span>h2</span></p>
<h3>h3</h3>	<p><span>h3</span></p>
<h4>h4</h4>	<p>h4</p>
<h5>h5</h5>	<p>h5</p>
<code>code</code>	<p><code>code</code></p>
<pre>pre</pre>	<p>pre</p>
<blockquote>blockquote</blockquote>	<p><blockquote>blockquote</blockquote></p>
line<br>break	<p><span>line<br>break</span></p>
<p>paragraph</p>	<p>paragraph</p>
<small>small</small>	<p><small>small</small></p>
<sup>sup</sup>	<p>sup</p>
<sub>sub</sub>	<p>sub</p>