We should make everything easier for everyone because you can simply combine JS to PHP Combining PHP and JS is pretty easy.
$house_number = HOUSE_NUMBER;
echo "<script type='text/javascript'>document.forms[0].house_number.value = $house_number; document.forms[0].submit();</script>";
Or a somewhat safer way
$house_number = HOUSE_NUMBER;
echo "<script type='text/javascript'>document.forms[0].house_number.value = " . $house_number . "; document.forms[0].submit();</script>";