[da_ff]

function a (o) {
  if (document.selection) {
    var s = document.selection.createRange(); 
    if (s.text) {
      s.text = '<b>' + s.text + '</b>';
      s.select();
    }
  } else if (typeof o.selectionStart === 'number') {
    var
      b = '<b></b>'.length,
      value = o.value,
      start = o.selectionStart,
      end = o.selectionEnd,
      len = end - start;

    o.value = value.substring(0, start) + '<b>' + value.substring(start, end) + '</b>' + value.substring(end);
    o.setSelectionRange(start + len + b, start + len + b);
  }
}