layer日期控件，开始时间不能大于结束时间

var start=laydate.render({
elem: '#beginTime', //指定元素
type: 'month',
format:'yyyy-MM',
done:function (value,date) {
end.config.min.month = date.month-1;
}
});

var end=laydate.render({
elem: '#endTime', //指定元素
type: 'month',
format: 'yyyy-MM',
min: new Date().getMonth(),
done: function (value, date) {
if ($.trim(value) == '') {
var curDate = new Date();
date = {'date': curDate.getDate(), 'month': curDate.getMonth() +1, 'year': curDate.getFullYear()};
}
start.config.max = date;
start.config.max.month = date.month -1;
}
})