var ie4 = (document.all) ? true : false;
var ns4 = (document.layers) ? true : false;
var ns6 = (document.getElementById && !document.all) ? true : false;

function writetolayer(lay,txt) {
    if (ie4) {
        document.all[lay].innerHTML = txt;
    }
    if (ns4) {
        document[lay].document.write(txt);
        document[lay].document.close();
    }
    if (ns6) {
        over = document.getElementById([lay]);
        range = document.createRange();
        range.setStartBefore(over);
        domfrag = range.createContextualFragment(txt);
        while (over.hasChildNodes()) {
            over.removeChild(over.lastChild);
        }
        over.appendChild(domfrag);
    }
}

function showlayer(lay) {
    if (ie4) {document.all[lay].style.visibility = "visible";}
    if (ns4) {document.layers[lay].visibility = "show";}
    if (ns6) {document.getElementById([lay]).style.display = "block";}
}

function hidelayer(lay) {
    if (ie4) {document.all[lay].style.visibility = "hidden";}
    if (ns4) {document.layers[lay].visibility = "hide";}
    if (ns6) {document.getElementById([lay]).style.display = "none";}
}