Second drop down list from drop down list using PHP

Question

I'm working on creating a drop down list that uses a name for the options (different cars). I would like to add a second dropdown list that uses the id from the first drop down list to create a drop down list of different models of each car.

I would like to just use PHP if possible and I believe it is. Here is my code for the first drop down.

function get_vehicle() {
    global $db;
    $query = $db->prepare("SELECT idmanufacturer, name FROM manufacturer");
    $query->execute();
    $vehicles = $query->fetchAll();

    if(isset($vehicles)) {
        echo "<label>Vehicle:</label>";
        echo "<select name='vehicle'>";
    foreach ($vehicles as $vehicle){
            echo '<option value="'.$vehicle['name'].'">'.$vehicle['name'].'</option>';
            }echo "</select>";
        echo "<br />";
    }
 }

Possible duplicate of [http://stackoverflow.com/questions/13112376/how-to-make-cascading-drop-down-lists-using-mysql-and-php](http://stackoverflow.com/questions/13112376/how-to-make-cascading-drop-down-lists-using-mysql-and-php) — Ganesh Salunkhe, Mar 05 '15 at 05:55
@GaneshSalunkhe, I can't see that its a duplicate. He or she is using ajax. I don't know anything at all about ajax. — Regina Shepherd Riddle, Mar 05 '15 at 06:00

score 2 · Answer 1 · edited Jan 08 '17 at 09:09

For this you need to create an ajax function.On change of first dropdown pass its value to the ajax request to any other page and by its id find all car models and display it on second dropdown. Here is an example:- //File name First.php

function get_vehicle() {

    global $db;

    $query = $db->prepare("SELECT idmanufacturer, name FROM manufacturer");

    $query->execute();
    $vehicles = $query->fetchAll();
    if(isset($vehicles)) {
        echo "<label>Vehicle:</label>";
        echo "<select name='vehicle' onselect="call_models(this)">";
    foreach ($vehicles as $vehicle){
            echo '<option value="'.$vehicle['id'].'">'.$vehicle['name'].'</option>';
            }echo "</select>";
        echo "<br />";
    }
 }

// this will print first select box

 get_vehicle() ;

/* this is second dropdown by default it will be disabled

<select name="cardmodels" id="models" disabled>
<option></option>
</select>

/************* Add ajax function ************/

<script type="text/javascript">

/***********  This function will get the value of first dropdown and will pass the value to the second.php where we will create function to retrieve all models of selected class after fetching this we will return all options of second class. After fetching this we will assign to the second dropdown.

***************/

    function call_models(cnt)
    {
    var model= $(cnt).val();    
    if(models)  {
    $.ajax({
    type: "POST",
    url: "Second.php",
    data: {model:model_car}
    })
    .done(function(responce) {
    if(responce!="Not_found") {
    $('#models').removeAttr( "disabled" );
    $('#models').html(responce);
    }
    });
    }
    }

</script>

/************** Second .php *********/ //File name First.php

    function get_models($id) {

        global $db;

        $query = $db->prepare("SELECT model_name FROM car_models where car_id ='".$id."' ");

        $query->execute();
        $models= $query->fetchAll();

        if($models) {

        foreach ($models as $model){
                echo '<option value="'.$model['name'].'">'.$model['name'].'</option>';
                }
        }
     }


if($_POST) {


get_models($_POST['model']);


} else {


echo "Not_found";

}

?>

I have been working on trying your example here and so far I can't get it to work. The fatal error says this: Fatal error: Call to undefined function call_models() in J:\XAMPP\htdocs\tire\includes\functions.php on line 110 - Your help will definitely be appreciated. God bless you. — Regina Shepherd Riddle, Mar 06 '15 at 05:47
I tried using it as javascript, but would prefer a pure php function that I could use to get the second drop down list, even if it is a little slower. Can you help me? I really want this to work and will use javascript if you can make it clear to me exactly how to use it. Thanks and God bless you. — Regina Shepherd Riddle, Mar 09 '15 at 05:44

Second drop down list from drop down list using PHP

1 Answers1