function setOpacity(key)
{
    //document.getElementById('posizione'+key).style.visibility='visible';
    //document.getElementById('posizione'+key+'_miniatura').style.visibility='visible';
    //changeOpac('cnt_container', 4);
}

function unsetOpacity(key)
{
    //document.getElementById('posizione'+key+'_miniatura').style.visibility='hidden';
    //changeOpac('cnt_container', 10);
}

//change the opacity for different browsers 
function changeOpac( id, opacity) { 
    var object = document.getElementById(id).style; 
    object.opacity = (opacity / 10); 
    object.MozOpacity = (opacity / 10); 
    object.KhtmlOpacity = (opacity * 10); 
    object.filter = "alpha(opacity=" + (opacity*10) + ")";
}