var timeout    = 100;    // ms
var closetimer    = 0;
var ddmenuitem    = 0;


function mopen(id)
{   
    mcancelclosetime();

    if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';

    ddmenuitem = document.getElementById(id);
    ddmenuitem.style.visibility = 'visible';

}

function mclose()
{
    if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
}

function mclosetime()
{
    closetimer = window.setTimeout(mclose, timeout);
}

function mcancelclosetime()
{
    if(closetimer)
    {
        window.clearTimeout(closetimer);
        closetimer = null;
    }
}

document.onclick = mclose;