I have a jQuery dropdown list that has two dropdowns. The first one is a list of cars and the second one shows the car's models. This is all working fine. Now I would like to use the selection selected by the user to search a database (MySQL) and find a specific element within the database. This just gives me the else within my code and once it gave me a undefined variable error message.
How can I code this so that I can access the variables and display a search result? Here is my code:
This is just an example of the jQuery I'm using - I'm actually using cars but this shows cities:
<select class="select" id="province" onchange="filterCity();">
  <option value="1">RM</option>
  <option value="2">FI</option>
</select>
 <select class="select" id="city" disabled>
  <option data-province="RM" value="1">ROMA</option>
  <option data-province="RM" value="2">ANGUILLARA SABAZIA</option>
  <option data-province="FI" value="3">FIRENZE</option>
  <option data-province="FI" value="4">PONTASSIEVE</option>
</select>
<span id="option-container" style="visibility: hidden; position:absolute;"></span>
<script>
    function filterCity(){
      var province = $("#province").find('option:selected').text(); // stores province
      $("#option-container").children().appendTo("#city"); // moves <option> contained in #option-container back to their <select>
      var toMove = $("#city").children("[data-province!='"+province+"']"); // selects city elements to move out
      toMove.appendTo("#option-container"); // moves city elements in #option-container
      $("#city").removeAttr("disabled"); // enables select
 };
</script>
And here is the code where I'm trying to access the searched for variable (this code is echoing wrong (the else)): I used the name="car" in the second select:
if (isset($_POST['car'])) {
        $_SESSION['car'] = $_POST['car'];
    $car = $_SESSION['car'];
}
function find_tire(){
    if (isset($_POST['car'])) {
        $_SESSION['car'] = $_POST['car'];
    $car = $_SESSION['car'];
}
    global $db;
    if (isset($car)) {
    $query = $db->prepare("SELECT idtires FROM vehicle WHERE idcarmodel = $car");
 $query->execute();
    $tire = $query->fetchAll();
    var_dump($query);}
if (isset($tire)) {
            echo "<ul>";
        foreach ($tire as $name) {
                echo "<li id='tiresearch'>";
                echo "Tire Size is Available: " . $name    ['idtires'];
                echo "</li>";
            }echo "</ul>";
    } else {
            echo "Wrong";
        }
  }
 
     
    