<?php
$link=mysqli_connect('147.32.164.26','test','a1234,'test')
 or die('Error: '.mysqli_error($link));

$s='insert into orderst (id_c,id_u,o_from,km1) values('.
   $_POST["id_c"].','.$_POST["id_u"].',now(),123456);';

if ($result=mysqli_query($link,$s) )
{
echo "Car #".$_POST["id_c"]." has been rented.";
}
else {
echo 'Error: '.mysqli_error($link);
}
mysqli_close($link); 
?>