<?php
$servername = "localhost";
$username = "admin";
$password = "senha";
$dbname = "eu_mydb";

// Cria conexao

$login=$_POST["login"];
$senha=$_POST["password"];
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection


if($login!=null)
{
$query = mysqli_query($conn,"SELECT * FROM Usuario WHERE (Login='$login' AND Senha='$senha'")or die(mysql_error());

$numrow = mysqli_num_rows($query);
if($numrow > 0)
{
        echo"<script>alert('Login valido');</script>";
    }


else
{
                 echo "<script>alert('nao cadastrado');</script>";
   }

   }
$conn->close();
?>