var timerID = null;

function closeall() 
{
    document.getElementById('dropdown1').style.visibility = "hidden";
    document.getElementById('dropdown2').style.visibility = "hidden";
    document.getElementById('dropdown2_1').style.visibility = "hidden";
    document.getElementById('dropdown2_2').style.visibility = "hidden";
}

function openclose(drop) 
{
    closeall();
    clearTimeout(timerID);
    document.getElementById(drop).style.visibility = "visible";
}


function openOnly(drop) 
{
    clearTimeout(timerID);
    document.getElementById(drop).style.visibility = "visible";
}


function closeOnly(drop) 
{
    clearTimeout(timerID);
    document.getElementById(drop).style.visibility = "hidden";
}