<?php
function issetFilmId($films_id){
	$handle = fopen("val.txt", "r");
	if ($handle) {
		while (($line = fgets($handle)) !== false) {
			if($line == $films_id){
				return TRUE;
			}
		}
		fclose($handle);
	} else {
		return FALSE;
	}
}

if (issetFilmId(10)) {
	echo "Exist";
}
else {
	echo("Not exist");
}