function paste_str(id,bb1,bb2)
{
 var str; var id=document.getElementById(id);
 if (id) if (document.selection)
 {
  id.focus();
  sel = document.selection.createRange();
  sel.text = bb1 + sel.text + bb2;
  sel.select();
  return;
 } else
 {
  var startPos = id.selectionStart; var endPos = id.selectionEnd;
  str = id.value.substring(startPos, endPos);
  id.value = id.value.substring(0, startPos) + bb1 + str + bb2 + id.value.substring(endPos, id.value.length);
  return;
 }
}