puppeteer/assets/js/8ec7c00f.09763c6e.js

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For example, a typical workflow goes like:",source:"@site/versioned_docs/version-20.2.0/guides/query-selectors-legacy.md",sourceDirName:"guides",slug:"/guides/query-selectors-legacy",permalink:"/guides/query-selectors-legacy",draft:!1,tags:[],version:"20.2.0",frontMatter:{}},c={},p=[{value:"CSS",id:"css",level:2},{value:"Example",id:"example",level:3},{value:"Built-in selectors",id:"built-in-selectors",level:2},{value:"Text selectors (<code>text/</code>)",id:"text-selectors-text",level:3},{value:"Example",id:"example-1",level:4},{value:"XPath selectors (<code>xpath/</code>)",id:"xpath-selectors-xpath",level:3},{value:"Example",id:"example-2",level:4},{value:"ARIA selectors (<code>aria/</code>)",id:"aria-selectors-aria",level:3},{value:"Example",id:"example-3",level:4},{value:"Pierce selectors (<code>pierce/</code>)",id:"pierce-selectors-pierce",level:3},{value:"Example",id:"example-4",level:4},{value:"Custom selectors",id:"custom-selectors",level:2}],u={toc:p};function m(e){var{components:t}=e,n=o(e,["components"]);return(0,r.kt)("wrapper",a({},u,n,{components:t,mdxType:"MDXLayout"}),(0,r.kt)("h1",a({},{id:"query-selectors-legacy"}),"Query Selectors (legacy)"),(0,r.kt)("p",null,"Queries are the primary mechanism for interacting with the DOM on your site. For example, a typical workflow goes like:"),(0,r.kt)("pre",null,(0,r.kt)("code",a({parentName:"pre"},{className:"language-ts"}),"// Import puppeteer\nimport puppeteer from 'puppeteer';\n\n(async () => {\n  // Launch the browser\n  const browser = await puppeteer.launch();\n\n  // Create a page\n  const page = await browser.newPage();\n\n  // Go to your site\n  await page.goto('YOUR_SITE');\n\n  // Query for an element handle.\n  const element = await page.waitForSelector('div > .class-name');\n\n  // Do something with element...\n  await element.click(); // Just an example.\n\n  // Dispose of handle\n  await element.dispose();\n\n  // Close browser.\n  await browser.close();\n})();\n")),(0,r.kt)("h2",a({},{id:"css"}),"CSS"),(0,r.kt)("p",null,"CSS selectors follow the CSS spec of the browser being automated. We provide some basic type deduction for CSS selectors (such as ",(0,r.kt)("inlineCode",{parentName:"p"},"HTMLInputElement")," for ",(0,r.kt)("inlineCode",{parentName:"p"},"input"),"), but any selector that contains no type information (such as ",(0,r.kt)("inlineCode",{parentName:"p"},".class-name"),") will need to be coerced manually using TypeScript's ",(0,r.kt)("inlineCode",{parentName:"p"},"as")," coercion mechanism."),(0,r.kt)("h3",a({},{id:"example"}),"Example"),(0,r.kt)("pre",null,(0,r.kt)("code",a({parentName:"pre"},{className:"language-ts"}),"// Automatic\nconst element = await page.waitForSelector('div > input');\n// Manual\nconst element = (await page.waitForSelector(\n  'div > .class-name-for-input'\n)) as HTMLInputElement;\n")),(0,r.kt)("h2",a({},{id:"built-in-selectors"}),"Built-in selectors"),(0,r.kt)("p",null,"Built-in selectors are Puppeteer's own class of selectors for doing things CSS cannot. Every built-in selector starts with a prefix ",(0,r.kt)("inlineCode",{parentName:"p"},".../")," to assist Puppeteer in distinguishing between CSS selectors and a built-in."),(0,r.kt)("h3",a({},{id:"text-selectors-text"}),"Text selectors (",(0,r.kt)("inlineCode",{parentName:"h3"},"text/"),")"),(0,r.kt)("p",null,'Text selectors will select "minimal" elements containing the given text, even within (open) shadow roots. Here, "minimum" means the deepest elements that contain a given text, but not their parents (which technically will also contain the given text).'),(0,r.kt)("h4",a({},{id:"example-1"}),"Example"),(0,r.kt)("pre",null,(0,r.kt)("code",a({parentName:"pre"},{className:"language-ts"}),"// Note we usually need type coercion since the type cannot be deduced, but for text selectors, `instanceof` checks may be better for runtime validation.\nconst element = await page.waitForSelector('text/My name is Jun');\n")),(0,r.kt)("h3",a({},{id:"xpath-selectors-xpath"}),"XPath selectors (",(0,r.kt)("inlineCode",{parentName:"h3"},"xpath/"),")"),(0,r.kt)("p",null,"XPath selectors will use the browser's native ",(0,r.kt)("a",a({parentName:"p"},{href:"https://developer.mozilla.org/en-US/docs/Web/API/Document/evaluate"}),(0,r.kt)("inlineCode",{parentName:"a"},"Document.evaluate"))," to query for elements."),(0,r.kt)("h4",a({},{id:"example-2"}),"Example"),(0,r.kt)("pre",null,(0,r.kt)("code",a({parentName:"pre"},{className:"language-ts"}),"// There is not type deduction for XPaths.\nconst node = await page.waitForSelector('xpath/h2');\n")),(0,r.kt)("h3",a({},{id:"aria-selectors-aria"}),"ARIA selectors (",(0,r.kt)("inlineCode",{parentName:"h3"},"aria/"),")"),(0,r.kt)("p",null,"ARIA selectors can be used to find elements with a given ARIA label. These labels are computed using Chrome's internal representation."),(0,r.kt)("h4",a({},{id:"example-3"}),"Example"),(0,r.kt)("pre",null,(0,r.kt)("code",a({parentName:"pre"},{className:"language-ts"}),"const node = await page.waitForSelector('aria/Button name');\n")),(0,r.kt)("h3",a({},{id:"pierce-selectors-pierce"}),"Pierce selectors (",(0,r.kt)("inlineCode",{parentName:"h3"},"pierce/"),")"),(0,r.kt)("p",null,"Pierce selectors will run the ",(0,r.kt)("inlineCode",{parentName:"p"},"querySelector*")," API on the document and all shadow roots to find an element."),(0,r.kt)("admonition",a({},{type:"danger"}),(0,r.kt)("p",{parentName:"admonition"},"Selectors will ",(0,r.kt)("strong",{parentName:"p"},"not")," ",(0,r.kt)("em",{parentName:"p"},"partially")," pierce through shadow roots. See the examples below.")),(0,r.kt)("h4",a({},{id:"example-4"}),"Example"),(0,r.kt)("p",null,"Suppose the HTML is"),(0,r.kt)("pre",null,(0,r.kt)("code",a({parentName:"pre"},{className:"language-html"}),"<div>\n  <custom-element>\n    <div></div>\n  </custom-element>\n</div>\n")),(0,r.kt)("p",null,"Then"),(0,r.kt)("pre",null,(0,r.kt)("code",a({parentName:"pre"},{className:"language-ts"}),"// This will be two elements because of the outer and inner div.\nexpect((await page.$$('pierce/div')).length).toBe(2);\n\n// Partial piercing doesn't work.\nexpect((await page.$$('pierce/div div')).length).toBe(0);\n")),(0,r.kt)("h2",a({},{id:"custom-selectors"}),"Custom selectors"),(0,r.kt)("p",null,"Puppeteer provides users the ability to add their own query selectors to Puppeteer using ",(0,r.kt)("a",a({parentName:"p"},{href:"/api/puppeteer.registercustomqueryhandler"}),"Puppeteer.registerCustomQueryHandler"),". This is useful for creating custom selectors based on framework objects or other vendor-specific objects."))}m.isMDXComponent=!0}}]);