< script language = "javascript" >
var getMonthWeek = function(a, b, c)
{
/*  
a = d = 當前日期  
b = 6 - w = 當前周的還有幾天過完(不算今天)  
a + b 的和在除以7 就是當天是當前月份的第幾周  
*/
        var date = new Date(a, parseInt(b) - 1, c),
            w = date.getDay(),
            d = date.getDate();
        return Math.ceil((d + 6 - w) / 7);
};
 
var getYearWeek = function(a, b, c) 
{
    /*  
    date1是當前日期 
    date2是當年第一天  
    d是當前日期是今年第多少天  
    用d + 當前年的第一天的周差距的和在除以7就是本年第幾周  
    */
        var date1 = new Date(a, parseInt(b) - 1, c),
            date2 = new Date(a, 0, 1),
            d = Math.round((date1.valueOf() - date2.valueOf()) / 86400000);
        
 
return Math.ceil((d + ((date2.getDay() + 1) - 1)) / 7);
};
today = new Date(); //獲取當前時間 
var y = today.getFullYear();
var m = today.getMonth() + 1;
var d = today.getDate();
document.write("今天是"+ m + "月的第 " + getMonthWeek(y, m, d) + " 周");
document.write("<br /><br />"+today.getHours()+":"+ today.getMinutes()+":"+ today.getSeconds());
 
< /script>