使用Ajax从数据库动态加载内容

So I'm new to Ajax, this is my first attempt at using it, hoping that someone can help me find my mistake. The goal is that I have a list of vehicle styles and in the database, I have Makes associated with specific styles. So when a radio button with a style is selected, it should populate a dropdown list with the Makes associated.

I got it working well on Chrome, but having issues with other browser such as IE and Safari.

Screen shot of it working on Chrome here: Link
Screen shot of it not working on Safari here: Link

The form name is: autoForm And the radio fields have an onclick event to call getMakes().

This is my function:

function getMakes() {
       $.post('getMake.php', {
            vehicleStyle: autoForm.style.value
        },
        function(output) {
               $('#vehicle-makes').hide();
            $('#vehicle-makes').html(output).slideDown("slow");
        });
}

Here is the PHP from getMake.php

PDO/database stuff up here^^ Leaving it out of the example
$list = '<label for="vehicle_make">Makes</label>
              <select name="vehicle_make"
                    class="form-control"
                    onchange="getModels()">
                    <option value="">Select One</option>';

    foreach ($results as $result) {
        $list .= '<option value="'.$result->make.'">'.$result->make.'</option>';
    }

    $list .= '</select>';

    echo $list;

So as you can see, it is communicating with the getMakes.php because it's bringing over the empty dropdown list - but it looks like it's not sending the data over to the PHP to pull associated data from the DB.

All help is appreciated, thank you!

So what I figured out is that this doesn't work in IE and Safari:

vehicleStyle: autoForm.style.value

I had to get the value of the input differently, and it worked.