버튼 클릭 시 AJAX로 PHP 함수를 실행하는 방법은 무엇입니까?

<input type="submit">

$(document).ready(function(){
    $('.button').click(function(){
        var action = $(this).val(); // Get the button's value (insert/select)
        $.post('ajax.php', { action: action }, function(response) {
            // Handle the server response here (e.g., display an alert)
        });
    });
});

if (isset($_POST['action'])) {
    switch ($_POST['action']) {
        case 'insert':
            insert();
            break;
        case 'select':
            select();
            break;
    }
}

function select() {
    echo "The select function is called.";
    exit;
}

function insert() {
    echo "The insert function is called.";
    exit;
}