var name = "blogCalendar";

// This function is quoted from Styleswitching JavaScript 
// http://jemimap.freeshell.org/style/scripts.html#styleswitcher
function readCookie(name) {
    var nameEQ = name + "=";
    var ca = document.cookie.split(';');
    for(var i=0;i < ca.length;i++) {
        var c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1,c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
    }
    return null;
}

var yearmonth = readCookie(name);
if (yearmonth) {
    var iframe = this.document.getElementsByTagName('iframe');
    iframe[0].setAttribute("src","http://www.happa.info/archives/calendar/" + yearmonth + "/index.php");
}