function change_box(nr) {  

    for(var i = 1; i < 3; i++) {
        document.getElementById('main_desc_'+i).className = 'inactive';
        document.getElementById('main_box_'+i).className = 'proddesc none';
    }
    
    document.getElementById('main_desc_'+nr).className='active';
    document.getElementById('main_box_'+nr).className='proddesc';
}

var k = 1;
function change_banner() {
	if(k == 1) k = 2;
	else k = 1;

	document.getElementById('banners').innerHTML = '<img src="/skins/user/shoper_red_1/images/b_banner'+k+'.gif">';
}

setInterval(change_banner, 5000);