Login System - PHP and JQuery [closed]

Hi, I am doing a login system and I have doubts about its security, it is very simple and it does Ajax by JQuery from a PHP page with MySQL, the code is this:

HTML:

<form id="loginForm" name="loginForm" action="teste.php" method="POST">
    <input type="text" name="loginUsuario" id="loginUsuario" class="input" value="NOME DE USÚARIO">
    <input type="text" name="loginSenha" id="loginSenha" class="input" value="SENHA">
    <input type="submit" name="loginEntrar" id="loginEntrar" class="input" value="ENTRAR">
</form>

JQuery:

<script>
$(document).ready(function() {

    $("#loginEntrar").click(function() {
        var loginLogin = $("#loginUsuario").val();
        var loginSenha = $("#loginSenha").val();
        $("#loginEntrar").prop('disabled', true);
        $.post('login.php', {
            login: loginLogin,
            senha: loginSenha
        }, function(resposta) {
            if (resposta == true) {
                $("#loginForm").submit();
            }
        }, 'html');
        return false;
    });

});
</script>

PHP: login.php

<?php

include "bd_connect.php";

$login=$_POST['login'];
$senha=$_POST['senha'];


$query = mysql_query("SELECT * FROM 'usuarios' WHERE login LIKE '$login' AND senha LIKE '$senha'") or die(mysql_error());
$totalres = mysql_num_rows($query);

if ($totalres == 1)
{
echo true;
}
else
{
echo false;
}

?>

How do I translate MySQL to mysqli and about this login method, is it safe?