My Javascript code follows.   The PasteHTML puts the string at the beginning of the editor's content, regardless of the original position of 'selectedhtml'

 

 

var editor1 = document.getElementById('');
var editor1doc = editor1.GetDocument();

var selectedhtml = editor1doc.selection.createRange().htmlText;

editor1.PasteHTML("**BEFORESELECTION**" + selectedhtml + "**AFTERSELECTION**");