mirror of
https://github.com/puppeteer/puppeteer
synced 2024-06-14 14:02:48 +00:00
53 lines
1.5 KiB
Markdown
53 lines
1.5 KiB
Markdown
<!-- Do not edit this file. It is automatically generated by API Documenter. -->
|
|
|
|
[Home](./index.md) > [puppeteer](./puppeteer.md) > [Page](./puppeteer.page.md) > [evaluateOnNewDocument](./puppeteer.page.evaluateonnewdocument.md)
|
|
|
|
## Page.evaluateOnNewDocument() method
|
|
|
|
Adds a function which would be invoked in one of the following scenarios:
|
|
|
|
- whenever the page is navigated
|
|
|
|
- whenever the child frame is attached or navigated. In this case, the function is invoked in the context of the newly attached frame.
|
|
|
|
The function is invoked after the document was created but before any of its scripts were run. This is useful to amend the JavaScript environment, e.g. to seed `Math.random`.
|
|
|
|
<b>Signature:</b>
|
|
|
|
```typescript
|
|
evaluateOnNewDocument(pageFunction: Function | string, ...args: unknown[]): Promise<void>;
|
|
```
|
|
|
|
## Parameters
|
|
|
|
| Parameter | Type | Description |
|
|
| --- | --- | --- |
|
|
| pageFunction | Function \| string | Function to be evaluated in browser context |
|
|
| args | unknown\[\] | Arguments to pass to <code>pageFunction</code> |
|
|
|
|
<b>Returns:</b>
|
|
|
|
Promise<void>
|
|
|
|
## Example
|
|
|
|
An example of overriding the navigator.languages property before the page loads:
|
|
|
|
```js
|
|
// preload.js
|
|
|
|
// overwrite the `languages` property to use a custom getter
|
|
Object.defineProperty(navigator, 'languages', {
|
|
get: function () {
|
|
return ['en-US', 'en', 'bn'];
|
|
},
|
|
});
|
|
|
|
// In your puppeteer script, assuming the preload.js file is
|
|
in same folder of our script
|
|
const preloadFile = fs.readFileSync('./preload.js', 'utf8');
|
|
await page.evaluateOnNewDocument(preloadFile);
|
|
|
|
```
|
|
|