function openDir( form ) { 

	var newIndex = form.fieldname.selectedIndex; 
	var target;

	switch (newIndex) {

	   case 0:

		alert( "Select a wall to visit from the drop-down menu." ); 
		break;

	   case 28:

		alert( "You may select one of the 4 original walls from the bottom of the list." ); 
		break;

	   default:

		cururl = form.fieldname.options[ newIndex ].value; 

		if ( newIndex > 28 ) {

			target = cururl;

		} else {

			target = cururl + ".html";
		}
	
		window.location.assign( target ); 
	} 
}