JavaScript(js)获取本周，本月，本季，本年，上月，上周，上季，去年，上二周，上二月的时间段的代码

function dateChange(name){

var beginTimeObject = document.getElementById("beginTime");

var endTimeObject = document.getElementById("endTime");

var beginTime;

var endTime;

var now = new Date();

var month = now.getMonth();

var year = now.getFullYear();

var day = now.getDate();

var wday = now.getDay();

switch(name){

case "tweek": //本周

var day  = now.getDay();

now.setDate(now.getDate() - (day -1));

beginTime = formatDate(now);

now.setDate(now.getDate() + 6);

endTime = formatDate(now);

break;

case "tmonth":  //本月

now.setDate(1);

beginTime = formatDate(now);

var days = getDays(now);

now.setDate(days);

endTime = formatDate(now);

break;

case "tquarter":   //本季

var m = now.getMonth() + 1;

var q = parseInt((m + 2 ) / 3 ); //得到第几季

m = q * 3 - 2;  //得到季的首月份

now.setMonth(m-1);

now.setDate(1);

beginTime = formatDate(now);

now.setMonth(now.getMonth() + 3);

now.setDate(0);

endTime = formatDate(now);

break;

case "tyear":    //本年

now.setMonth(0);

now.setDate(1);

beginTime = formatDate(now);

now.setMonth(11);

now.setDate(31);

endTime = formatDate(now);

break;

case "today":    //今天

beginTime = formatDate(now);

endTime = beginTime;

break;

case "pweek":    //上周

var day  = now.getDay();

now.setDate(now.getDate() - (day -1) - 7 );

beginTime = formatDate(now);

now.setDate(now.getDate() + 6);

endTime = formatDate(now);

break;

case "pmonth":    //上月

now.setDate(1);

now.setMonth(now.getMonth() -1 );

beginTime = formatDate(now);

var days = getDays(now);

now.setDate(days);

endTime = formatDate(now);

break;

case "pquarter":    //上季

var m = now.getMonth() + 1;

var q = parseInt((m + 2 ) / 3 ); //得到第几季

m = q * 3 - 2;  //得到季的首月份

m = m-3 ; //上季

now.setMonth(m-1);

now.setDate(1);

beginTime = formatDate(now);

now.setMonth(now.getMonth() + 3);

now.setDate(0);

endTime = formatDate(now);

break;

case "pyear":    //去年

now.setFullYear(now.getFullYear() -1 );

now.setMonth(0);

now.setDate(1);

beginTime = formatDate(now);

now.setMonth(11);

now.setDate(31);

endTime = formatDate(now);

break;

case "p2week":    //上二周

var day  = now.getDay();

now.setDate(now.getDate() - (day -1) - 7 *2);

beginTime = formatDate(now);

now.setDate(now.getDate() + 6 + 7);

endTime = formatDate(now);

break;

case "p2month":    //上二月

now.setDate(1);

now.setMonth(now.getMonth() -1*2 );

beginTime = formatDate(now);

now.setMonth(now.getMonth() + 2);

now.setDate(0);

endTime = formatDate(now);

break;

case "customize":    //自定义

beginTime = "";

endTime = "";

break;

}

beginTimeObject.value = beginTime;

endTimeObject.value = endTime;