<?php
function validString($str, $max, $start = 0) {
	if (isset($str) && strlen($str) > 0) {
		return substr(htmlspecialchars($str), $start, $max);
	}
	return false;
}
function validFloat($f) {
    $value = floatval(filter_var($f, FILTER_SANITIZE_NUMBER_FLOAT, FILTER_FLAG_ALLOW_FRACTION));
	if (is_float($value)) {
		return floatval($value);
	}
	return false;
}
?>