function AddString(string, textvalue) {
  var TheForm;
  var StrPromt;
  var tmp;

  TheForm = document.comment;
  
  if (string == 'B' | string == 'i' | string == 'U') {
    switch (string) {
      case 'B': 
        tmp = prompt(textvalue);
        StrPromt = '<strong>'+tmp+'</strong>'; 
      break;
      case 'i': 
        tmp = prompt(textvalue);
        StrPromt='<em>'+tmp+'</em>'; 
      break;
      case 'U': 
        tmp = prompt(textvalue);
        StrPromt='<u>'+tmp+'</u>'; 
      break;
      default: 
        StrPromt='';
    }
    string = StrPromt;
    if (!tmp)
      string = false;
  }
  
  if (string != false)
    TheForm.comment_text.value = TheForm.comment_text.value + string;
  
  TheForm.comment_text.focus();
  
  return false;
}