//   计算日期为当年的第几周     
//   用法：    
//   获取   2008-7-5  为当年的第几周     
//   返回:  28     
// document.write(  weekOfYear(2008 ,   7 ,   5)  );
function weekOfYear(year, month, day) {
    //   year       年     
    //   month     月     
    //   day         日     
    //   每周从周日开始     
    var date1 = new Date(year, 0, 1);
    var date2 = new Date(year, month - 1, day, 1);
    var dayMS = 24 * 60 * 60 * 1000;
    var firstDay = (7 - date1.getDay()) * dayMS;
    var weekMS = 7 * dayMS;
    date1 = date1.getTime();
    date2 = date2.getTime();
    return Math.ceil((date2 - date1 - firstDay) / weekMS) + 1;
}

function switchTel(labelId) {
    var currentWeekIndex = weekOfYear(new Date().getFullYear(), new Date().getMonth() + 1, new Date().getDate());
    var tels = ["64096692", "64096929", "64096928"];
    var newTels = new Array();
    var tmp = currentWeekIndex % tels.length;

    for (var i = tmp; i < tels.length; i++) {
        newTels.push(tels[i]);
    }

    var l = tels.length - newTels.length;
    for (var i = 0; i < l; i++) {
        newTels.push(tels[i]);
    }
    document.getElementById(labelId).innerText = newTels.join(" / ");
}