function showhide(id) {
    var d = document, n = id.split('');
    for (i = 1; i <= 9; i++) {
        if (!d.getElementById(n[0] + i)) continue;
        d.getElementById(n[0] + i).style.display = (i == n[1]) ? 'block' : 'none';
    }
}

function showhide2(sel) {
    var d = document, v = sel.options[sel.selectedIndex].value, n = v.split('');
    if (v) {
        for (i = 1; i <= 9; i++) {
            if (!d.getElementById(n[0] + i)) continue;
            d.getElementById(n[0] + i).style.display = (i == n[1]) ? 'block' : 'none';
        }
    }
}