var drops = new Array(3);

if (document.getElementById) {
    document.onclick = hideDrops;
}

function setElement() {
    if (document.getElementById) {
        for (var i = 0; i < 3; i++) {
            drops[i] = document.getElementById("drop" + i);
        }
    }
}

function showDrop(index) {
    if (document.getElementById) {
        hideDrops();
        drops[index].style.visibility = "visible";
    }
}

function hideDrops() {
    if (document.getElementById) {
        for (var i = 0; i < 3; i++) { drops[i].style.visibility = "hidden"; }
    }
}