<titledata-rh="true">WebWorker class | Puppeteer</title><metadata-rh="true"name="viewport"content="width=device-width,initial-scale=1"><metadata-rh="true"name="twitter:card"content="summary_large_image"><metadata-rh="true"property="og:url"content="https://pptr.dev/api/puppeteer.webworker"><metadata-rh="true"property="og:locale"content="en"><metadata-rh="true"name="docsearch:language"content="en"><metadata-rh="true"name="docsearch:counter"content="2"><metadata-rh="true"property="og:title"content="WebWorker class | Puppeteer"><metadata-rh="true"name="description"content="This class represents a WebWorker."><metadata-rh="true"property="og:description"content="This class represents a WebWorker."><linkdata-rh="true"rel="icon"href="/img/favicon.ico"><linkdata-rh="true"rel="canonical"href="https://pptr.dev/api/puppeteer.webworker"><linkdata-rh="true"rel="alternate"href="https://pptr.dev/api/puppeteer.webworker"hreflang="en"><linkdata-rh="true"rel="alternate"href="https://pptr.dev/api/puppeteer.webworker"hreflang="x-default"><linkdata-rh="true"rel="preconnect"href="https://DVKY664LG7-dsn.algolia.net"crossorigin="anonymous"><linkrel="search"type="application/opensearchdescription+xml"title="Puppeteer"href="/opensearch.xml">
<p>This class represents a <ahref="https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API"target="_blank"rel="noopener noreferrer">WebWorker</a>.</p>
<h4class="anchor anchorWithStickyNavbar_LWe7"id="signature">Signature:<ahref="#signature"class="hash-link"aria-label="Direct link to Signature:"title="Direct link to Signature:"></a></h4>
<h2class="anchor anchorWithStickyNavbar_LWe7"id="remarks">Remarks<ahref="#remarks"class="hash-link"aria-label="Direct link to Remarks"title="Direct link to Remarks"></a></h2>
<p>The events <code>workercreated</code> and <code>workerdestroyed</code> are emitted on the page object to signal the worker lifecycle.</p>
<p>The constructor for this class is marked as internal. Third-party code should not call the constructor directly or create subclasses that extend the <code>WebWorker</code> class.</p>
<h2class="anchor anchorWithStickyNavbar_LWe7"id="example">Example<ahref="#example"class="hash-link"aria-label="Direct link to Example"title="Direct link to Example"></a></h2>
<h2class="anchor anchorWithStickyNavbar_LWe7"id="properties">Properties<ahref="#properties"class="hash-link"aria-label="Direct link to Properties"title="Direct link to Properties"></a></h2>
<table><thead><tr><th>Property</th><th>Modifiers</th><th>Type</th><th>Description</th></tr></thead><tbody><tr><td>client</td><td><code>readonly</code></td><td><ahref="/api/puppeteer.cdpsession">CDPSession</a></td><td>The CDP session client the WebWorker belongs to.</td></tr></tbody></table>
<h2class="anchor anchorWithStickyNavbar_LWe7"id="methods">Methods<ahref="#methods"class="hash-link"aria-label="Direct link to Methods"title="Direct link to Methods"></a></h2>
<table><thead><tr><th>Method</th><th>Modifiers</th><th>Description</th></tr></thead><tbody><tr><td><ahref="/api/puppeteer.webworker.evaluate">evaluate(pageFunction, args)</a></td><td></td><td>If the function passed to the <code>worker.evaluate</code> returns a Promise, then <code>worker.evaluate</code> would wait for the promise to resolve and return its value. If the function passed to the <code>worker.evaluate</code> returns a non-serializable value, then <code>worker.evaluate</code> resolves to <code>undefined</code>. DevTools Protocol also supports transferring some additional values that are not serializable by <code>JSON</code>: <code>-0</code>, <code>NaN</code>, <code>Infinity</code>, <code>-Infinity</code>, and bigint literals. Shortcut for <code>await worker.executionContext()).evaluate(pageFunction, ...args)</code>.</td></tr><tr><td><ahref="/api/puppeteer.webworker.evaluatehandle">evaluateHandle(pageFunction, args)</a></td><td></td><td>The only difference between <code>worker.evaluate</code> and <code>worker.evaluateHandle</code> is that <code>worker.evaluateHandle</code> returns in-page object (JSHandle). If the function passed to the <code>worker.evaluateHandle</code> returns a <code>Promise</code>, then <code>worker.evaluateHandle</code> would wait for the promise to resolve and return its value. Shortcut for <code>await worker.executionContext()).evaluateHandle(pageFunction, ...args)</code></td></tr><tr><td><ahref="/api/puppeteer.webworker.url">url()</a></td><td></td><td>The URL of this web worker.</td></tr></tbody></table></div></article><navclass="pagination-nav docusaurus-mt-lg"aria-label="Docs pages"><aclass="pagination-nav__link pagination-nav__link--prev"href="/api/puppeteer.page.workers"><divclass="pagination-nav__sublabel">Previous</div><divclass="pagination-nav__label">Page.workers</div></a><aclass="pagination-nav__link pagination-nav__link--next"href="/api/puppeteer.webworker.evaluate"><divclass="pagination-nav__sublabel">Next</div><divclass="pagination-nav__label">WebWorker.evaluate</div></a></nav></div></div><divclass="col col--3"><divclass="tableOfContents_bqdL thin-scrollbar theme-doc-toc-desktop"><ulclass="table-of-contents table-of-contents__left-border"><li><ahref="#remarks"class="table-of-contents__link toc-highlight">Remarks</a></li><li><ahref="#example"class="table-of-contents__link toc-highlight">Example</a></li><li><ahref="#properties"class="table-of-contents__link toc-highlight">Properties</a></li><li><ahref="#methods"class="table-of-contents__link toc-highlight">Methods</a></li></ul></div></div></div></div></main></div></div></div><footerclass="footer footer--dark"><divclass="container container-fluid"><divclass="row footer__links"><divclass="col footer__col"><divclass="footer__title">Community</div><ulclass="footer__items clean-list"><liclass="footer__item"><ahref="https://stackoverflow.com/questions/tagged/puppeteer"target="_blank"rel="noopener noreferrer"class="footer__link-item">Stack Overflow<svgwidth="13.5"height="13.5"aria-hidden="true"viewBox="0 0 24 24"class="iconExternalLink_nPIU"><pathfill="currentColor"d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li><liclass="footer__item"><ahref="https://twitter.com/chromedevtools"target="_blank"rel="noopener noreferrer"class="footer__link-item">Twitter<svgwidth="13.5"height="13.5"aria-hidden="true"viewBox="0 0 24 24"class="iconExternalLink_nPIU"><pathfill="currentColor"d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li><liclass="footer__item"><ahref="https://goo.gle/devtools-youtube"target="_blank"rel="noopener noreferrer"class="footer__link-item">YouTube<svgwidth="13.5"height="13.5"aria-hidden="true"viewBox="0 0 24 24"class="iconExternalLink_nPIU"><pathfill="currentColor"d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg><
