Checks whether all given parameters are numeric (Same as php-vanilla "is_numeric" but as variadic function).

isNumeric.php

// Checks whether all given parameters are numeric.
// Usage: $validCoordinates = isNumeric($_GET['p1Lat'], $_GET['p1Lon']));
function isNumeric() {
    $numberOfArguments = func_num_args();
    $arguments = func_get_args();

    return count(array_filter($arguments, 'is_numeric')) === $numberOfArguments;
}