$(document).ready(function(){
$("#formKonstrukt").on("submit", function(e){
e.preventDefault();
var form = $(this).serialize();
var Formdata = new FormData($(form)[0]);
$.ajax({
url: "orderBuy.php",
type: "POST",
processData: false,
contentType: false,
data: FormData,
success: function(data){
alert(data);
}
});
});
});<form method="POST" id="formKonstrukt" enctype="multipart/form-data">
<button type="submit" class="btn btn-primary" id="orderFutbolka">Заказать</button>
</form>