uaName = navigator.userAgent;
appName = navigator.appVersion;
var fontSizeUnit = "px";
var perOrder = 2;
var defaultSize = 13;
var currentSize = defaultSize;

function fsize( CMD ){
  if( CMD == "larger" ){
    var newSize = Number(currentSize + perOrder);
  }
  if( CMD == "smaller" ){
    if ( currentSize != perOrder ){
      var newSize = Number(currentSize - perOrder);
    }
    else{
      var newSize = Number(currentSize);
    }
  }
  if( CMD == "default" ){
    var newSize = defaultSize;
  }
  if( document.layers ){
    window.alert( "���̋@�\��Netscape Communicator4.x�ł͓��삵�܂���" );
    return false;
  }
  else if(( appName.indexOf("Mac",0) != -1 ) && ( uaName.indexOf("MSIE 4.0",0) != -1 )){
    window.alert( "Sorry! MacIE4.0 is not supported." );
    return false;
  }

  else if( document.body ){

    document.body.style.fontSize = newSize + fontSizeUnit;
    currentSize = newSize;
  }

}