var isNavigator = navigator.appName=='Netscape';

//setTimeout("letAppletGetFocus();", 1000);//再给一次机会

function letAppletGetFocus()
{
   if ( window.document.applets.length > 0 )
   {
      window.document.applets[0].requestDefaultFocus(isNavigator);
   }
}
if( isNavigator )
{
   document.captureEvents( Event.KEYUP );
}
document.onkeyup = letAppletGetFocusOnKeyNPressed;

function letAppletGetFocusOnKeyNPressed(e)
{
	var keyCode, onlyAltDown;

	if( e )//For Navigator 4.0x, it is true
	{
	   ;
	}
	else if( window.event )//For Internet Explorer 4.0x, it is true
	{
	   e = window.event;
	}
	else//Unsupported
	{
	   return;
	}
	onlyAltDown = e.altKey && e.ctrlKey == false && e.shiftKey == false;

	if ( onlyAltDown == false )
	{
	   return;
	}
	if( typeof( e.keyCode ) == 'number'  )//For Internet Explorer 4.0x, it is true
	{
	   keyCode = e.keyCode;
	}
	else if( typeof( e.which ) == 'number' )//For Navigator 4.0x, it is true
	{
	   keyCode = e.which;
	}
	else if( typeof( e.charCode ) == 'number'  )//Unknown
	{
	   keyCode = e.charCode;
	}
	else
	{
	   return;
	}
	if ( keyCode == 78 || keyCode == 77)//78='N'
	{
	   letAppletGetFocus();
	}
}