The Anki note editor button row has s1, s2 and s3 buttons.
Three new buttons.
This is an Anki 2.0 plugin. I have no plans of updating it. People that are interrested in this are welcome to take this over.

Another add-on to add buttons to the note editor. This adds buttons to wrap text in spans.

By default there are three buttons, s1, s2 and s3, that wrap the text selected in a note’s field in <span class="styleN">/</span> tags. (N = 1, 2, 3). It is up to the user to set up the card styling to make use these classes.

The changes made by the add-on are invisible in the card editor, and on the cards, unless styling for the classes is added.
Unlike the italic or bold buttons, clicking theese buttons twice does not un-wrap the text, but adds a second span.

This add-on is based on Thomas Tempé’s strikethrough button add-on.