上个星期，上个月

<script type="text/javascript"> 
//个位补全
window.singular = function(n){
    var newNum;
    newNum = n < 10 ? '0' + n : n;
    return newNum;
}
//时间转字符串
window.date2Str = function(date){
    return date.getFullYear()+'-'+singular(date.getMonth()+1)+'-'+singular(date.getDate());
}

function getLastWeek(date){
	var _monday = date.getDay() == 0 ? 7 : date.getDay();
	var date1 = new Date();
	date1.setDate(date.getDate() - _monday - 6);
	var date2 = new Date();
	date2.setDate(date.getDate() - _monday);
	return [date2Str(date1), date2Str(date2)];
}

function getLastMonth(date){
	var _month = date.getMonth();
	var year = date.getFullYear();
	return [year + '-' + singular(_month) + '-01', year + '-' + singular(_month) + '-31'];
}


var date = new Date();
var _lastWeek = getLastWeek(date);
console.log(_lastWeek);

var _lastMonth = getLastMonth(date);
console.log(_lastMonth)

</script>