## LoadStart event

Triggered when the [loader](/js/elements_object/create.md#stripe_elements-options-loader) UI is mounted to the DOM and ready to be displayed.

**This event is only emitted from the `payment`, `linkAuthentication`, and `address` Elements.**

**Syntax:** `element.on(...)`

- `event` ('loaderstart') **required**
  The name of the event.
In this case, `loaderstart`.

- `handler` (function) **required**
  `handler(event) => void` is a **callback function** that you provide that will be called when the event is fired.

When called it will be passed an event object with the following properties:

  - `elementType` (string)
    The type of element that emitted this event.

### Handle an Element loaderstart event

```js
paymentElement.on('loaderstart', function(event) {
  // Handle loaderstart event
});
```

```es_next
paymentElement.on('loaderstart', (event) => {
  // Handle loaderstart event
});
```