function menu_link(num)
{
	switch(num)

	{

	  case 1:window.location="catalog.htm" ;break;

	  case 2:window.location="catalog.htm" ;break;

	  case 3:window.location="catalog.htm" ;break;

	  case 4:window.location="catalog.htm" ;break;

	  case 5:window.location="catalog.htm" ;break;

	  case 6:window.location="catalog.htm" ;break;

	  case 7:window.location="catalog.htm" ;break;

	  case 8:window.location="catalog.htm" ;break;

	  case 9:window.location="catalog.htm" ;break;

	  case 10:window.location="catalog.htm" ;break;

      case 11:window.location="product_01.htm" ;break;

	  case 12:window.location="product_02.htm" ;break;

	  case 13:window.location="product_03.htm" ;break;

	  case 14:window.location="product_04.htm" ;break;

	  case 15:window.location="catalog.htm" ;break;

	  case 16:window.location="catalog.htm" ;break;

	  case 17:window.location="catalog.htm" ;break;

	  case 18:window.location="catalog.htm" ;break;

	  case 19:window.location="catalog.htm" ;break;

	  case 20:window.location="catalog.htm" ;break;

	}
}