So as the title says I'm curious, can user change the ID of an element through browser? I have a list of inputs - checkboxes, when you click on one of them ajax takes ID of that element and uses it to get data from database, so basically what I'm thinking is that if it is somehow possible to change the ID of the element my database wouldn't be secured. If that's possible, how I should protect it?

Okay, So I get the idea that it wouldn't be secured, If I'd use this way:

```
<?php

$mysqli = new mysqli("host", "user", "password", "database");

$usuario = $mysqli->real_escape_string($_POST["usuario"]);
$clave = $mysqli->real_escape_string($_POST["clave"]);

$sql='  SELECT * FROM usuarios 
        WHERE username="'.$usuario.'" 
        AND pass="'.$clave.'"
     ';

$mysqli->query($sql);

$mysqli->close();
?>

```

would it be enough, or there aren't actually safe enough way to protect data?