//设置中国时区
 
$time = time();
$timeBetween=['08:00:00','18:00:00'];
    
echo getTime($time,$timeBetween);
    
function getTime($time, $timeBetween)
    {
        $checkDayStr = date('Y-m-d ', time());
        $timeBegin1 = strtotime($checkDayStr . $timeBetween[0]);
        $timeEnd1 = strtotime($checkDayStr . $timeBetween[1]);
        if ($time > $timeBegin1 && $time < $timeEnd1) {
            echo $time . "在区间【" . $timeBetween[0] . "~" . $timeBetween[1] . "】内";
        } else {
            echo "不在区间内";
        }
    }