关于js获取前几周，几个月的js小脚本

       最近在做项目的时候，遇到了获取上几周，上几个月的的开始时间，和结束时间，在网上搜罗了一遍并没有完全满足自己需求的，就根据网上的例子，简单修改了一下，供大家参考：

        

var getWeek=function(mark){
    var week = "日一二三四五六".split("")[new Date().getDay()];

    var endTime  ;

    if(week == "一"){
        endTime = addDate(new Date(),-1)
    } else if(week == "二"){
        endTime = addDate(new Date(),-2)

    } else if(week == "三"){
        endTime = addDate(new Date(),-3)

    } else if(week == "四"){
        endTime = addDate(new Date(),-4)

    } else if(week == "五"){
        endTime = addDate(new Date(),-5)

    } else if(week == "六"){
        endTime = addDate(new Date(),-6)

    } else if(week == "日") {
        endTime = addDate(new Date(), -7)
    }

    var endTimeStr = formatDate(endTime);

    addDate(endTime,-7*mark+1)

    var startTime = formatDate(endTime);

    return startTime+"~"+endTimeStr;
}

var addDate= function(date,n){
    date.setDate(date.getDate()+n);
    return date;
};

下面是格式化代码：

var formatDate = function(date){
    var year = date.getFullYear()+'-';
    var month = "";
    if(date.getMonth()+1<10){
        month = "0"+(date.getMonth()+1)+'-';
    }else{
        month = (date.getMonth()+1)+'-';
    }

    var day = "";
    if(date.getDate()<10){
        day = "0"+date.getDate();
    }else{
        day = date.getDate();
    }
    return year+month+day;
};