日付を比較する
JavaScript
var st = new Date("2022-10-01").getTime(),
    ed = new Date("2022-10-31").getTime(),
    now = new Date().getTime();
if( st <= now && now <= ed ){
  echo "10月です";
}
var st = new Date("2022-10-01").getTime(),
    ed = new Date("2022-10-31").getTime(),
    now = new Date().getTime();
if( st <= now && now <= ed ){
  echo "10月です";
}