Ajax it does nothing when sending parameters to a php page

Question

I am a beginner using ajax and am trying to change the status of reading a book by clicking an image. I had the code working but without ajax. Now I have no php error but not a change in mysql. The code:

<script type="text/javascript">
    function sendState(state_id){
        var hd_haveread = $("#hd_haveread").val();
        var hd_toread = $("#hd_toread").val();
        var hd_reading = $("#hd_reading").val();

        var val = 0;
        var baseurl = "img/";

        switch(state_id){
            case 1:
                if (hd_haveread == "0"){
                    document.getElementById('hd_haveread').value = "1";
                    document.getElementById('hd_toread').value = "0";
                    document.getElementById('hd_reading').value = "0";
                    val = 1;
                }
                else{
                    document.getElementById('hd_haveread').value = "0";
                    val = 0;
                }
            break;
            case 3:
                if (hd_toread == "0"){
                    document.getElementById('hd_toread').value = "1";
                    document.getElementById('hd_haveread').value = "0";
                    document.getElementById('hd_reading').value = "0";
                    val = 1;
                }
                else{
                    document.getElementById('hd_toread').value = "0";
                    val = 0;
                }
            break;
            case 2:
                if (hd_reading == "0"){
                    document.getElementById('hd_reading').value = "1";
                    document.getElementById('hd_haveread').value = "0";
                    document.getElementById('hd_toread').value = "0";
                    val = 1;
                }
                else{
                    document.getElementById('hd_reading').value = "0";
                    val = 0;
                }
            break;
        }

        var parameters = {
            "book" : <?php echo $id_book; ?>,
            "state" : state_id,
            "val" : val
        };
        $.ajax({
            cache: false,
            data:  parameters,
            url:   'change_state_ajax.php',
            type:  'post',
            dataType: "html",
            beforeSend: function (){
            },
            success: function (response){
                switch(state_id){
                    case 1:
                        if (hd_haveread == "0"){
                            $("#img_haveread1").css("display","none");
                            $("#img_haveread2").css("display","inline-block");
                            $("#img_toread1").css("display","inline-block");
                            $("#img_toread2").css("display","none");
                            $("#img_reading1").css("display","inline-block");
                            $("#img_reading2").css("display","none");
                        }
                        else{
                            $("#img_haveread1").css("display","inline-block");
                            $("#img_haveread2").css("display","none");
                        }
                    break;
                    case 3:
                        if (hd_toread == "0"){
                            $("#img_haveread1").css("display","inline-block");
                            $("#img_haveread2").css("display","none");
                            $("#img_toread1").css("display","none");
                            $("#img_toread2").css("display","inline-block");
                            $("#img_reading1").css("display","inline-block");
                            $("#img_reading2").css("display","none");
                        }
                        else{
                            $("#img_toread1").css("display","inline-block");
                            $("#img_toread2").css("display","none");
                        }
                    break;
                    case 2:
                        if (hd_reading == "0"){
                            $("#img_haveread1").css("display","inline-block");
                            $("#img_haveread2").css("display","none");
                            $("#img_toread1").css("display","inline-block");
                            $("#img_toread2").css("display","none");
                            $("#img_reading1").css("display","none");
                            $("#img_reading2").css("display","inline-block");
                        }
                        else{
                            $("#img_reading1").css("display","inline-block");
                            $("#img_reading2").css("display","none");
                        }
                    break;
                }
            }
        });
    }
</script>

And the change_state_ajax.php code:

<?php

    if(isset($_POST['book']) && isset($_POST['state']) && isset($_POST['val'])){
        include 'connection.php';
        include('php_lib/config.ini.php');
        include_once('php_lib/login.lib.php');

        $lib_id = $_POST['book'];
        $state = $_POST['state'];
        $val = $_POST['val'];

        $result=changeState($lib_id, $state, $val); 
        echo $result;
    }

    function changeState($lib_id, $state, $val){
        session_start();
        $usu_id = $_SESSION['USSER']['id'];
        $mark = 0;
        $pos = 0;

        $query = $pdo->prepare('SELECT uliusu_id, ulilib_id, uliedl_id FROM '.TABLE_USSERS_BOOKS.' WHERE ulilib_id = :fil_lib_id AND uliusu_id = :fil_usu_id');
        $query->bindParam(':fil_lib_id', $lib_id, PDO::PARAM_INT);
        $query->bindParam(':fil_usu_id', $usu_id, PDO::PARAM_INT);
        $query->execute();

        while($row = $query->fetch(PDO::FETCH_OBJ)){
            $mark = 1;
            $state_actual = $row->uliedl_id;
        }

        if($mark == 0){
            $query = $pdo->prepare('INSERT INTO '.TABLE_USSERS_BOOKS.' (uliusu_id, ulilib_id, uliedl_id, uli_posicion, uli_fecha) VALUES (:fil_usu_id, :fil_lib_id, :fil_edl_id, :fil_pos, NOW())');
            $query->bindParam(':fil_usu_id', $usu_id, PDO::PARAM_INT);
            $query->bindParam(':fil_lib_id', $lib_id, PDO::PARAM_INT);
            $query->bindParam(':fil_edl_id', $state, PDO::PARAM_INT);
            $query->bindParam(':fil_pos', $pos, PDO::PARAM_INT);
            $query->execute();
        }else{
            if($state == $state_actual){
                $query = $pdo->prepare('DELETE FROM '.TABLE_USSERS_BOOKS.' WHERE ulilib_id = :fil_lib_id AND uliusu_id = :fil_usu_id');
                $query->bindParam(':fil_usu_id', $usu_id, PDO::PARAM_INT);
                $queryquery->bindParam(':fil_lib_id', $lib_id, PDO::PARAM_INT);
                $query->execute();
            }else{
                $query = $pdo->prepare('UPDATE '.TABLE_USSERS_BOOKS.' SET uliedl_id = :fil_edl_id WHERE ulilib_id = :fil_lib_id AND uliusu_id = :fil_usu_id');
                $query->bindParam(':fil_edl_id', $state, PDO::PARAM_INT);
                $query->bindParam(':fil_usu_id', $usu_id, PDO::PARAM_INT);
                $query->bindParam(':fil_lib_id', $lib_id, PDO::PARAM_INT);
                $query->execute();
            }
        }

        if($state == 1){
            $result = 0;
        }else{
            $result = 1;
        }

        return $result;
    }
?>

Can anyone help me solve this?

Thanks.

Answer 1

Things I noticed:

1) First you are POSTing but in PHP, you are using $_GET.

2) you are passing "book", "estado", "val" but are trying to get "book", "state", "val", so it never enters into if condition

Answer 2

You are not checking for the proper variables. Your JavaScript passes a var called estado but you check in PHP for a var called state.

And because you require all three variables to be set your condition fails.

Also like Hank said in his comment your jQuery.Ajax call uses POST (type: 'post',) but then in your PHP script you check GET variables which of course are not set.

Either change you jQuery call type to GET or change the checking in your PHP script to POST

if(isset($_POST['book']) && isset($_POST['state']) && isset($_POST['val'])){
    include 'connection.php';
    include('php_lib/config.ini.php');
    include_once('php_lib/login.lib.php');

    $lib_id = $_POST['book'];
    $state = $_POST['state'];
    $val = $_POST['val'];

    $result=changeState($lib_id, $state, $val); 
    echo $result;
}