opera = (navigator.userAgent.indexOf('Opera') >= 0)? true : false;
ie = (document.all && !opera)? true : false;
dom = (document.getElementById && !ie && !opera)? true : false;

function existsElem( elemId )
{
    if (dom) return document.getElementById(elemId);
    else if (ie) return document.all[elemId];
}


function putElem(elemId,displayValue)
{
    if (dom) document.getElementById(elemId).style.display = (displayValue)? displayValue : "block";
    else if (ie) document.all[elemId].style.display = "block";
}

function removeElem(elemId)
{
    if (dom) document.getElementById(elemId).style.display = "none";
    else if (ie) document.all[elemId].style.display = "none";
}

function changeImageSrc( imgId, imgSrc )
{
    if (dom) document.getElementById(imgId).src = imgSrc;
    else if (ie) document.all[imgId].src = imgSrc;
}

mainOpen = new Array();

function changeMenu( id )
{
    if (! mainOpen[id] )
    {
       mainOpen[id] = false;
    }
    if (mainOpen[id])
    {
        i = 0;
        while ( existsElem( id + '_' + i ) )
        {
            removeElem( id + '_' + i );
            i++;
        }
        changeImageSrc( 'i'+id, '/img/plus.gif' );
    } else
    {
        i = 0;
        while ( existsElem( id + '_' + i ) )
        {
            putElem( id + '_' + i );
            i++;
        }
        changeImageSrc( 'i'+id, '/img/minus.gif' );
    }
    mainOpen[id] = ! mainOpen[id];
}


if (dom || ie)
{
    document.writeln('<style type="text/css">');
    document.writeln('.subMenu \{ display: none; \}');
    document.writeln('</style>');
}