# Event handlers Through the use of event handlers you can trigger an [action](https://docs.appfarm.io/reference/actions) to run either automatically or due to user interaction. Automatic events occur when an app is in use, such as when an [app](https://docs.appfarm.io/reference/apps) or [view](https://docs.appfarm.io/reference/apps/ui/views) is loaded, or a [timer](https://docs.appfarm.io/apps/app-settings#timers). User interaction events can include clicking a [UI component,](https://docs.appfarm.io/library/ui-components) updating a value in a data input component, or running a [keyboard shortcut](https://docs.appfarm.io/apps/ui/views#keyboard-event-handlers). ## Automatic events

Event	Description
On App Load	Triggered when the app is loaded/refreshed after data sources have been populated but before the UI is shown to the user. Configured in App settings.
On App Loaded	Triggered when the app is loaded/refreshed and after the UI is shown to the user. Configured in App settings.
On Online/On Offline	For Offline Apps. Configured in App settings.
On Visible/On Hidden	Triggered when an App goes inactive or active. Configured in App settings.
On Browser History Change	Can be used to trigger an action when the browser history changes. Configured and documented in App settings.
On Timeout	Trigged when a timer expires. Configured in App settings.
On View Load/Dialog Open/Drawer Open	Triggered before a view is loaded/opened. Configured in view properties.
On View Loaded/Dialog Opened/Drawer Opened	Triggered after a view is loaded/opened. Configured in view properties.
On Load	Triggered after a component is loaded. Configured in component properties for Image and Animated component.
On Complete	Triggered after after a component has completed its purpose. Configured in component properties for Animated component.

## User interaction events User interaction events are configured in [UI components](https://docs.appfarm.io/library/ui-components). For details on how to add keyboard event handlers, see [Views](https://docs.appfarm.io/apps/ui/views#keyboard-event-handlers).

Event	Description
On [Location] Click	Triggered when the user clicks or taps on a component (like a Button) or part of a component (like a Table row). Can be used to make containers and Image components clickable. If used in a data iterator, the element clicked will contain the object in context.
On Hover Start	Triggered when the mouse pointer enters a container. Use Conditional styles to style a component on hover.
On Hover End	Triggered when the mouse pointer leaves a container.
On Double Click	Triggered when double clicking a container
On Right Click	Triggered when right clicking a container
On Drag Start	Triggered when a user starts to drag a component within a container that has Enable Draggable selected.
On Drop	Triggered when a user drops a component within a container that has Enable Drop Area selected.
On File Paste	Triggered when a file is pasted on a container with Enable File Drop selected. Can be used to run an action with Create file object to upload the file.
On File Drop	Triggered when a file is dropped on a container with Enable File Drop selected. Can be used to run an action with Create file object to upload the file.
On File Over	Triggered when a file is dragged over a container with Enable File Drop selected. Can be used to toggle visual feedback.
On File Out	Triggered when a file is dragged over and then out of a container with Enable File Drop selected. Can be used to toggle visual feedback.
On Viewport Enter	Triggered when a container with Enable Listener selected enters the viewport, usually on scroll.
On Viewport Leave	Triggered when a container with Enable Listener selected leaves the viewport, usually on scroll.
On Focus	Triggered when a Text edit component receives focus due to a user clicking on or using the keyboard to select the component.
On Lost Focus	Triggered when a Text edit component loses focus due to a user clicking away or using the keyboard to select another component.
On Enter	Triggered when the `Enter/Return` key is pressed and a Text edit component has focus. Useful when the component is used for searching to execute the search.
On Value Change	Triggered after a value has changed in a data input component. The previous value can be sent as an action param.
On Open	Available on UI Components Select and Multi select. Triggered when the droplist is opened.
On Close	Available on UI Components Select and Multi select. Triggered when the droplist is closed.

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