js获取某周、某月、上月、某季度的开始日期、结束日期及判断日期第几周

/** 
 * 获取某周、某月、上月、某季度的开始日期、结束日期及判断日期第几周 
 */ 

//格式化日期：yyyy-MM-dd     
function formatDate(date) {      
    var myyear = date.getFullYear();     
    var mymonth = date.getMonth()+1;     
    var myweekday = date.getDate();      
         
    if(mymonth < 10){     
        mymonth = "0" + mymonth;     
    }      
    if(myweekday < 10){     
        myweekday = "0" + myweekday;     
    }     
    return (myyear+"-"+mymonth + "-" + myweekday);      
}      
    
//获得某月的天数     
function getMonthDays(paraYear,paraMonth){     
    var monthStartDate = new Date(paraYear, paraMonth, 1);      
    var monthEndDate = new Date(paraYear, paraMonth + 1, 1);      
    var   days   =   (monthEndDate   -   monthStartDate)/(1000   *   60   *   60   *   24);      
    return   days;      
}      
    
//获得某周的开始日期     
function getWeekStartDate(paraYear,paraMonth,paraDay,paraDayOfWeek) {      
    var weekStartDate = new Date(paraYear, paraMonth, paraDay + 1 - paraDayOfWeek);      
    return formatDate(weekStartDate);     
}      
    
//获得某周的结束日期     
function getWeekEndDate(paraYear,paraMonth,paraDay,paraDayOfWeek) {      
    var weekEndDate = new Date(paraYear, paraMonth, paraDay + (7 - paraDayOfWeek));      
    return formatDate(weekEndDate);     
}      
    
//获得某月的开始日期     
function getMonthStartDate(paraYear,paraMonth){     
    var monthStartDate = new Date(paraYear, paraMonth, 1);      
    return formatDate(monthStartDate);     
}     
    
//获得某月的结束日期     
function getMonthEndDate(paraYear,paraMonth){
    var monthEndDate = new Date(paraYear,paraMonth, getMonthDays(paraYear,paraMonth));      
    return formatDate(monthEndDate);     
}     
 
//获得上月开始时间  
function getLastMonthStartDate(paraYear, lastMonth){  
    var lastMonthStartDate = new Date(paraYear, lastMonth, 1);  
    return formatDate(lastMonthStartDate);    
}  
 
//获得上月结束时间  
function getLastMonthEndDate(paraYear, lastMonth, lastMonth){  
    var lastMonthEndDate = new Date(paraYear, lastMonth, getMonthDays(lastMonth));  
    return formatDate(lastMonthEndDate);    
}  
    
//获得某季度的开始日期     
function getQuarterStartDate(paraYear,paraSeason){     
    switch (paraSeason){     
        case '1' : return paraYear+"-01-01";
        case '2' : return paraYear+"-04-01";
        case '3' : return paraYear+"-07-01";
        case '4' : return paraYear+"-10-01";
    }
}     
    
//获得某季度的结束日期     
function getQuarterEndDate(paraYear,paraSeason){     
    switch (paraSeason){     
     case '1' : return paraYear+"-03-31";
     case '2' : return paraYear+"-06-30";
     case '3' : return paraYear+"-09-30";
     case '4' : return paraYear+"-12-31";
    }   
}

 

//获取某年某周的开始日期
function getBeginDateOfWeek(paraYear, weekIndex){
    var firstDay = GetFirstWeekBegDay(paraYear);
    //7*24*3600000 是一星期的时间毫秒数,(JS中的日期精确到毫秒)
    var time=(weekIndex-1)*7*24*3600000;
    var beginDay = firstDay;
    //为日期对象 date 重新设置成时间 time
    beginDay.setTime(firstDay.valueOf()+time);
    return formatDate(beginDay);
}

 

//获取某年某周的结束日期
function getEndDateOfWeek(paraYear, weekIndex){
    var firstDay = GetFirstWeekBegDay(paraYear);
    //7*24*3600000 是一星期的时间毫秒数,(JS中的日期精确到毫秒)
    var time=(weekIndex-1)*7*24*3600000;
    var weekTime = 6*24*3600000;
    var endDay = firstDay;
    //为日期对象 date 重新设置成时间 time
    endDay.setTime(firstDay.valueOf()+weekTime+time);
    return formatDate(endDay);
}

 

//获取日期为某年的第几周
function GetWeekIndex(dateobj) {
    var firstDay = GetFirstWeekBegDay(dateobj.getFullYear());
    if (dateobj < firstDay) {
      firstDay = GetFirstWeekBegDay(dateobj.getFullYear() - 1);
    }
    d = Math.floor((dateobj.valueOf() - firstDay.valueOf()) / 86400000);
    return Math.floor(d / 7) + 1;  
}

//获取某年的第一天
function GetFirstWeekBegDay(year) {
    var tempdate = new Date(year, 0, 1);
    var temp = tempdate.getDay();
    if (temp == 1){
       return tempdate;
    }
    temp = temp == 0 ? 7 : temp;
    tempdate = tempdate.setDate(tempdate.getDate() + (8 - temp));
    return new Date(tempdate);   
}