<?php
function course($amount, $from, $to) {
 
$data = file_get_contents("http://www.google.com/ig/calculator?hl=ru&q=$amount$from=?$to");
 
$data = explode('"', $data);
 
$course = round(substr(($data[3]), 0, strpos(($data[3]), ' ')), 2);
 
return $course;
 
}
 
?>

echo course(100.55, 'RUR', 'USD');