connection to database with phonegap

Good morning everyone, we are studying phonegap a powerful framework cross-platform and easy to design, what I do not understand is the connection to a database through ajax or jquery . I put something of what I wear and I hope you can please help me with my doubt that is driving me crazy.

I have a login form, the classic:

                          Code                                        Nip                                              

and my function with jquery to pass the data to my server and be able to communicate it with the login.php file that validates. which is inside the body so that the button can recognize it

<script>
function enviar_variables(){
    var datosCodigo = $("#codigo").val();
    var datosNip = $("#nip").val();

    $.post("https://juanssa91.000webhostapp.com/proyecto/login.php", {codigo:datosCodigo, nip:datosNip}, function(respuesta){
        alert(respuesta);
    });
}     
</script>

Well, it happens that when the executable shows the interface, I try to insert the data, I press the button, but nothing, it does not do anything.