function toggleObjectVisibility(obj_id)
{
    _toggleObjectVisibility(getObject(obj_id))
}

function _toggleObjectVisibility(obj)
{
    if(obj && document.getElementsByTagName)
    {
        if(obj.style.visibility == 'visible')
        {
            obj.style.display = 'none';
            obj.style.visibility = 'hidden';
        }
        else
        {
            obj.style.display = '';
            obj.style.visibility = 'visible';
        }
    }
}

function getObject(objectId) {
    // cross-browser function to get an object's style object given its id
    if(document.getElementById && document.getElementById(objectId)) {
    // W3C DOM
    return document.getElementById(objectId);
    } else if (document.all && document.all(objectId)) {
    // MSIE 4 DOM
    return document.all(objectId);
    } else if (document.layers && document.layers[objectId]) {
    // NN 4 DOM.. note: this won't find nested layers
    return document.layers[objectId];
    } else {
    return false;
    }
}