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Version: 16.1.0

Page.waitForFunction() method

Waits for a function to finish evaluating in the page's context.


class Page {
Params extends unknown[],
Func extends EvaluateFunc<Params> = EvaluateFunc<Params>
pageFunction: Func | string,
options?: {
timeout?: number;
polling?: string | number;
...args: Params
): Promise<HandleFor<Awaited<ReturnType<Func>>>>;


pageFunctionFunc | stringFunction to be evaluated in browser context
options{ timeout?: number; polling?: string | number; }(Optional) Optional waiting parameters - polling - An interval at which the pageFunction is executed, defaults to raf. If polling is a number, then it is treated as an interval in milliseconds at which the function would be executed. If polling is a string, then it can be one of the following values: - raf - to constantly execute pageFunction in requestAnimationFrame callback. This is the tightest polling mode which is suitable to observe styling changes. - mutation- to execute pageFunction on every DOM mutation. - timeout - maximum time to wait for in milliseconds. Defaults to 30000 (30 seconds). Pass 0 to disable timeout. The default value can be changed by using the Page.setDefaultTimeout() method.
argsParamsArguments to pass to pageFunction



A Promise which resolves to a JSHandle/ElementHandle of the the pageFunction's return value.

Example 1

The Page.waitForFunction() can be used to observe viewport size change:

const puppeteer = require('puppeteer');
(async () => {
const browser = await puppeteer.launch();
const page = await browser.newPage();
const watchDog = page.waitForFunction('window.innerWidth < 100');
await page.setViewport({width: 50, height: 50});
await watchDog;
await browser.close();

Example 2

To pass arguments from node.js to the predicate of Page.waitForFunction() function:

const selector = '.foo';
await page.waitForFunction(
selector => !!document.querySelector(selector),

Example 3

The predicate of Page.waitForFunction() can be asynchronous too:

const username = 'github-username';
await page.waitForFunction(
async username => {
const githubResponse = await fetch(
const githubUser = await githubResponse.json();
// show the avatar
const img = document.createElement('img');
img.src = githubUser.avatar_url;
// wait 3 seconds
await new Promise((resolve, reject) => setTimeout(resolve, 3000));