function showHide(item) {
    if (document.getElementById) {
        var mItem = document.getElementById(item).style;
    } else if (document.all) {
        var mItem = document.all[item].style;
    } else if (document.layers) {
        var mItem = document.layers[item].style;
    }
    mItem.display = mItem.display == "block" ? "none" : "block";
}