<?php
$start = "8:00";
$end = "5:00";
$now = "10:00";
//Check if we are within the set time
$start = Date("Hi", strtotime($start));
$end = Date("Hi", strtotime($end));
$now = Date("Hi", strtotime($now));
if($start < $now && $end > $now){
//We need to validate before sending.
echo "Good";
}