判断当天是周几

    function showTime() {
        var day = new Date();
        var year = day.getFullYear();
        var month = day.getMonth() + 1;
        var date = day.getDate();
        var days = day.getDay();
        var hours = day.getHours();
        var minutes = day.getMinutes();
        var second = day.getSeconds();
        switch (days) {
            case 1:
                rs = '一';
                break;

            case 2:
                rs = '二';
                break;

            case 3:
                rs = '三';
                break;

            case 4:
                rs = '四';
                break;

            case 5:
                rs = '五';
                break;

            case 6:
                rs = '六';
                break;

            case 7:
                rs = '日';
                break;

        }
        document.getElementById("nine").innerHTML = '今天是' + year + '年' + month + '月' + date + '日' + '星期' + rs

        + hours + '时' + minutes + '分' + second + '秒'
    }
    window.onload = showTime