AJAX call to return success or fail

I have a button which calls a function onClick and passes a couple of parameters. I need to use AJAX to pass these two parameters to the controller and onsuccess do something client-side. Here's the button and the ajax call:

<button type="button" class="btn btn-default" onclick="addComponent(@item.ID, @item.VendorID)">Add</button>

function addComponent(componentId, vendorId) {
$.ajax({
                type: 'POST',
                url: '@Url.Action("WriteSupportComponent")',
                contentType: false,
                dataType: 'json',
                data: { "componentId": componentId, "vendorId": vendorId },
                success: function (response) {
                    console.log('returned success');$('#' + componentId).remove();
                    console.log('removed tr');
                },
                error: function (ex) {
                    console.log('returned failed: ' + ex.responseText);
                }
            });
}

How do I need to structure the controller to do something (write to db in this case) and then return success or failed back to the function?

Thanks in advance
Adam