---
title: "BeforeUnloadEvent | JavaScript maps SDK"
description: "Documentation for MapTiler SDK"
---

> For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL.

# Variable BeforeUnloadEvent

BeforeUnloadEvent: { prototype: [BeforeUnloadEvent](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.BeforeUnloadEvent/); new (): [BeforeUnloadEvent](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.BeforeUnloadEvent/) }

#### Type Declaration

-   -   new (): [BeforeUnloadEvent](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.BeforeUnloadEvent/)
    -   #### Returns [BeforeUnloadEvent](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.BeforeUnloadEvent/)
        
-   ##### prototype: [BeforeUnloadEvent](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.BeforeUnloadEvent/)