function getPositionX( oElement )
{
    var iReturnValue = 0;
    while( oElement != null ) {
        iReturnValue += oElement.offsetLeft;
        oElement = oElement.offsetParent;
    }
    return iReturnValue;
}

function getPositionY( oElement )
{
    var iReturnValue = 0;
    while( oElement != null ) {
        iReturnValue += oElement.offsetTop;
        oElement = oElement.offsetParent;
    }
    return iReturnValue;
}

function setPosition(mainnav, subnav)
{
    var eSubnav = document.getElementById(subnav);
    var eMainnav = document.getElementById(mainnav);
    
    
    
    if(eSubnav.style.display == 'block') {
        eSubnav.style.display = 'none';	
    } else {
        eSubnav.style.display = 'block';	
        var topPosition = (getPositionY(eMainnav) - eSubnav.offsetHeight - 4);
        var leftPosition = getPositionX(eMainnav);
    			
        eSubnav.style.top = topPosition.toString() + 'px';
        eSubnav.style.left = leftPosition.toString() + 'px';
        eSubnav.style.width = eMainnav.offsetWidth  + 'px';
    }
}