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[Home](./index.md) &gt; [puppeteer](./puppeteer.md) &gt; [Protocol](./puppeteer.protocol.md) &gt; [Page](./puppeteer.protocol.page.md) &gt; [JavascriptDialogOpeningEvent](./puppeteer.protocol.page.javascriptdialogopeningevent.md)

## Protocol.Page.JavascriptDialogOpeningEvent interface

Fired when a JavaScript initiated dialog (alert, confirm, prompt, or onbeforeunload) is about to open.

<b>Signature:</b>

```typescript
export interface JavascriptDialogOpeningEvent 
```

## Properties

|  Property | Type | Description |
|  --- | --- | --- |
|  [defaultPrompt](./puppeteer.protocol.page.javascriptdialogopeningevent.defaultprompt.md) | string | Default dialog prompt. |
|  [hasBrowserHandler](./puppeteer.protocol.page.javascriptdialogopeningevent.hasbrowserhandler.md) | boolean | True iff browser is capable showing or acting on the given dialog. When browser has no dialog handler for given target, calling alert while Page domain is engaged will stall the page execution. Execution can be resumed via calling Page.handleJavaScriptDialog. |
|  [message](./puppeteer.protocol.page.javascriptdialogopeningevent.message.md) | string | Message that will be displayed by the dialog. |
|  [type](./puppeteer.protocol.page.javascriptdialogopeningevent.type.md) | [DialogType](./puppeteer.protocol.page.dialogtype.md) | Dialog type. |
|  [url](./puppeteer.protocol.page.javascriptdialogopeningevent.url.md) | string | Frame url. |