function confirmUpdate (frm) 
{ 
    for (i=0; i<frm.length; i++) 
    {
        if (frm.elements[i].name.indexOf("VacantCheckBox") !=-1) 
        {
            if(frm.elements[i].checked) 
            {
                return confirm ('Are you sure you want to update the unit status(es)?')
            }
        }
    }
}