var currentmonth;
function changeMonth(monthStr){
    if(monthStr == "all"){
        document.getElementById("calendardiv").className = "displayall";
    }
    else{
        var selectedmonth = document.getElementById(monthStr + "_inner")
        if(document.getElementById("calendardiv").className != "")
            {document.getElementById("calendardiv").className = "";}
        if(currentmonth){
            currentmonth.parentNode.className = "hiddenmonth";        
        }
        currentmonth = selectedmonth;
        selectedmonth.parentNode.className = "activemonth";
    }
}