Set cursor to specific position on specific line in a textarea

I've updated your fiddle see: http://jsfiddle.net/eghpf/2/

I've added var currentPosition which is used in this method

function setSelectionRange(input, selectionStart, selectionEnd) {
  if (input.setSelectionRange) {
    input.focus();
    input.setSelectionRange(selectionStart, selectionEnd);
  }
  else if (input.createTextRange) {
    var range = input.createTextRange();
    range.collapse(true);
    range.moveEnd('character', selectionEnd);
    range.moveStart('character', selectionStart);
    range.select();
  }
}

Which comes from this jQuery Set Cursor Position in Text Area

What happens (is the reason why the cursor is always on the last position); is when you call $('#systemNotesbuilder').val(arrayOfLines.join("\n")); the entire value gets overwritten with a new value placing the cursor after that new value. The call to set the cursor is (and should) be after that call.