I've found some really interesting! The execCommand function applies many useful features. But is it possible to work with OWN wraps? Like:
document.execCommand("styleWithCSS", false, "<span class='own-class'>");
Everything related i've found was pretty old… so maybe one of you knows a good workaround or something.
Thanks to dandavis.
The following works very well:
document.execCommand("insertHTML", false, "<span class='own-class'>"+ document.getSelection()+"</span>");