haw can i call php function through Javascript

function getLongitude($place)
       {
          $urlc="http://maps.google.com/maps/api/geocode/json?address=".$place."&sensor=false";
          $geocode=file_get_contents($urlc);
	  $output= json_decode($geocode);
	
	$longitude = $output->results[0]->geometry->location->lng;
       return $longitude;
       }
finction getLatitude($place)
        {
        $urlc="http://maps.google.com/maps/api/geocode/json?address=".$place."&sensor=false";
       $geocode=file_get_contents($urlc);
	$output= json_decode($geocode);
	$latitude = $output->results[0]->geometry->location->lat;
        return $latitude;
	}

<script Languge="JavaScript>
function calculate()
 {
   var place= document.zodiac.PlaceOfBirth.value;
   document.zodiac.latitude.value= getLatitude(place)// call php function
   document.zodiac.latitude.value= getLatitude(place)//call php function
}
</script>