// JavaScript Document
	



function box_navigation( typ ) {
	/* back forward */
	var hidden_box = 0;
	var display_box = 0;
	
	if( typ == 'back' ) {
		hidden_box  = box_navigation_no;
		display_box = box_navigation_no-1;
	}
	else {
		hidden_box  = box_navigation_no;
		display_box = box_navigation_no+1;
	}
	
	document.getElementById('text' + hidden_box ).style.display = 'none';
	document.getElementById('text' + display_box ).style.display = 'block';
	
	document.getElementById('back').style.display = ( display_box <= 1 ) ? 'none' : 'block';
	document.getElementById('forward').style.display = ( display_box >= box_navigation_max ) ? 'none' : 'block';
	
	
	box_navigation_no = display_box;
	
}