<script src="http://code.jquery.com/jquery-1.9.0.js"></script>
<script src="http://code.jquery.com/jquery-migrate-1.0.0.js"></script>

<form method='post'>
    <input type="text" name="id" id="id" placeholder="mail adress" />
    <input type="text" name="pass" id="pass" placeholder="password" />
    <input type="submit" name="login" id="login" value="login" />
</form>

<script type='text/javascript'>
    $('#id').on('input', function () {
        alert('text changed');
    });
</script>