<center>![tag.png](https://steemitimages.com/DQmXiqdSwUnqLV7JvmurhDtJQZaMmceesky8asthLSvLL3E/tag.png)</center>

Steemit posts support a limited subset of HTML that can be mixed with the Markdown syntax.
While Markdown is documented (click on ['Markdown Styling Guide'](https://guides.github.com/features/mastering-markdown/) in the editor view), I was not able to find any detailed documentation for HTML in Steemit posts.
I thought that I could [do it myself](https://youtu.be/BYbOkRye4gs) and gathered the information from the [source code of Condenser](https://github.com/steemit/condenser), the official Steemit UI.
This following list of tags, attributes and classes is my interpretation of the code. I hope it helps. Please keep in mind that this is not officially documented and Steemit may change the [whitelitsted](https://en.wikipedia.org/wiki/Whitelist) HTML in the future. Also, please let me know in the comments if you find any mistakes or missing information.

## Tags that allow attributes
* `a` [(Reference)](https://www.w3schools.com/tags/tag_a.asp)
  * Attributes
    * href
    * rel
* `div` [(Reference)](https://www.w3schools.com/tags/tag_div.asp)
  * Attributes
    * class
      * Allowed class values
        * pull-right
        * pull-left
        * text-justify
        * text-rtl
        * text-center
        * text-right
        * videoWrapper
        * phishy
    * title
* `iframe` [(Reference)](https://www.w3schools.com/tags/tag_iframe.asp)
  * Attributes
    * src
        * Supports only youtube, vimeo and soundcloud
    * width
    * height
    * frameborder
    * allowfullscreen
    * webkitallowfullscreen
    * mozallowfullscreen
* `img` [(Reference)](https://www.w3schools.com/tags/tag_img.asp)
  * Attributes
    * src
    * alt
* `td` [(Reference)](https://www.w3schools.com/tags/tag_td.asp)
  * Attributes
    * style

## Tags without attributes
* `b`           [(Reference)](https://www.w3schools.com/tags/tag_b.asp)
* `blockquote`  [(Reference)](https://www.w3schools.com/tags/tag_blockquote.asp)
* `br`          [(Reference)](https://www.w3schools.com/tags/tag_br.asp)
* `center`      [(Reference)](https://www.w3schools.com/tags/tag_center.asp)
* `code`        [(Reference)](https://www.w3schools.com/tags/tag_code.asp)
* `del`         [(Reference)](https://www.w3schools.com/tags/tag_del.asp)
* `em`          [(Reference)](https://www.w3schools.com/tags/tag_em.asp)
* `h1`          [(Reference)](https://www.w3schools.com/tags/tag_h1.asp)
* `h2`          [(Reference)](https://www.w3schools.com/tags/tag_h2.asp)
* `h3`          [(Reference)](https://www.w3schools.com/tags/tag_h3.asp)
* `h4`          [(Reference)](https://www.w3schools.com/tags/tag_h4.asp)
* `h5`          [(Reference)](https://www.w3schools.com/tags/tag_h5.asp)
* `h6`          [(Reference)](https://www.w3schools.com/tags/tag_h6.asp)
* `hr`          [(Reference)](https://www.w3schools.com/tags/tag_hr.asp)
* `i`           [(Reference)](https://www.w3schools.com/tags/tag_i.asp)
* `li`          [(Reference)](https://www.w3schools.com/tags/tag_li.asp)
* `ol`          [(Reference)](https://www.w3schools.com/tags/tag_ol.asp)
* `p`           [(Reference)](https://www.w3schools.com/tags/tag_p.asp)
* `pre`         [(Reference)](https://www.w3schools.com/tags/tag_pre.asp)
* `q`           [(Reference)](https://www.w3schools.com/tags/tag_q.asp)
* `strike`      [(Reference)](https://www.w3schools.com/tags/tag_strike.asp)
* `strong`      [(Reference)](https://www.w3schools.com/tags/tag_strong.asp)
* `sub`         [(Reference)](https://www.w3schools.com/tags/tag_sub.asp)
* `sup`         [(Reference)](https://www.w3schools.com/tags/tag_sup.asp)
* `table`       [(Reference)](https://www.w3schools.com/tags/tag_table.asp)
* `tbody`       [(Reference)](https://www.w3schools.com/tags/tag_tbody.asp)
* `th`          [(Reference)](https://www.w3schools.com/tags/tag_th.asp)
* `thead`       [(Reference)](https://www.w3schools.com/tags/tag_thead.asp)
* `tr`          [(Reference)](https://www.w3schools.com/tags/tag_tr.asp)
* `ul`          [(Reference)](https://www.w3schools.com/tags/tag_ul.asp)

Furthermore, [HTML entities](https://www.w3schools.com/html/html_entities.asp) like `&nbsp;` are allowed.

As @dbooster pointed out, Steemit removes HTML comments from the markup. Besides of [obscure Markdown voodoo](https://stackoverflow.com/questions/4823468/comments-in-markdown#20885980), there seems to be no good way to have comments in articles.

Based on this information, I am happy to be able to offer you this helpful snippet:

```
<center>
<div class="phishy">&#128293;&#128293;&#128293;UPVOTERS ARE MORE SUCCESSFUL&#128293;&#128293;&#128293;</div><br>
<div class="phishy">&#128293;&#128293;&#128293;RESTEEMERS LIVE LONGER&#128293;&#128293;&#128293;</div>
</center>
```
<br>

It should produce following output:

<center>
<div class="phishy">&#128293;&#128293;&#128293;UPVOTERS ARE MORE SUCCESSFUL&#128293;&#128293;&#128293;</div><br>
<div class="phishy">&#128293;&#128293;&#128293;RESTEEMERS LIVE LONGER&#128293;&#128293;&#128293;</div>
</center>

<hr/>
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<div class="pull-right">© 2017 @snug</div>
</div>