ie8以下，new Date() 特定一天，返回NaN的问题的处理

        function getDate(dateStr) {
            var isoExp = /^\s*(\d{4})-(\d\d)-(\d\d)\s*$/; //正则
            var date = new Date(NaN);
            var parts = isoExp.exec(dateStr); //正则验证
            if (parts) {
                var month = Number(parts[2]);
                //设置时间
                date.setFullYear(parts[1], month - 1, parts[3]);
                //判断是否正确
                if (month != date.getMonth() + 1) {
                    date.setTime(NaN);
                }
            }
            return date;
        }