Преобразование bb кодов

function BBcode(id)
 {
  //тут id например b
  var button_id = attribs = id;
  if (/\[.*\]/.test(attribs)) {attribs = attribs.replace(/.*\[(.*)\]/, ' $1'); } else attribs = '';  
  var start = '['+button_id+attribs+']';
  var end = '[/'+button_id+']';
  element = document.getElementById('ChatTextArea');
  if (document.selection)
   {
    element.focus();
    sel = document.selection.createRange();
    sel.text = start + sel.text + end;
   }
  else if (element.selectionStart || element.selectionStart == '0')
   {
    element.focus();
    var startPos = element.selectionStart;
    var endPos = element.selectionEnd;
    element.value = element.value.substring(0, startPos) + start + element.value.substring(startPos, endPos) + end +
    element.value.substring(endPos, element.value.length);
   }
  else
   {
    element.value += start + end;
   }
 
 }