function closeDiv(whichLayer)
{
if (document.getElementById(whichLayer).style.display = "") {
document.getElementById(whichLayer).style.display = "none";
}
else {
document.getElementById(whichLayer).style.display = "none";
}
}

<!-- use to check for open tabs on service.html when user comes from categories on index.html //->
function closeTabDiv(whichLayer)
{
if (document.getElementById(whichLayer).style.display = "block") {
document.getElementById(whichLayer).style.display = "none";
}
else {
document.getElementById(whichLayer).style.display = "none";
}
}

function toggleDiv(whichLayer)
{
if (document.getElementById(whichLayer).style.display = "none") {
document.getElementById(whichLayer).style.display = "";
}
else {
document.getElementById(whichLayer).style.display = "none";
}
}

function openDiv(whichLayer)
{
if (document.getElementById(whichLayer).style.display = "none") {
document.getElementById(whichLayer).style.display = "";
}
else {
document.getElementById(whichLayer).style.display = "";
}
}