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定位器

介绍

Introduction

定位器 是 Playwright 自动等待和重试能力的核心部分。简而言之,定位器代表了一种随时在页面上查找元素的方法。

Locators are the central piece of Playwright's auto-waiting and retry-ability. In a nutshell, locators represent a way to find element(s) on the page at any moment.

快速指南

Quick Guide

这些是推荐的内置定位器。

These are the recommended built in locators.

await page.getByLabel('User Name').fill('John');

await page.getByLabel('Password').fill('secret-password');

await page.getByRole('button', { name: 'Sign in' }).click();

await expect(page.getByText('Welcome, John!')).toBeVisible();

定位元素

Locating elements

Playwright 带有多个内置定位器。为了使测试具有弹性,我们建议优先考虑面向用户的属性和显式契约,例如 page.getByRole()

Playwright comes with multiple built-in locators. To make tests resilient, we recommend prioritizing user-facing attributes and explicit contracts such as page.getByRole().

例如,考虑以下 DOM 结构。

For example, consider the following DOM structure.

http://localhost:3000
<button>Sign in</button>

根据其角色 button 和名称 "登入" 找到该元素。

Locate the element by its role of button with name "Sign in".

await page.getByRole('button', { name: 'Sign in' }).click();
注意

使用 代码生成器 生成定位器,然后根据需要对其进行编辑。

Use the code generator to generate a locator, and then edit it as you'd like.

每次将定位器用于操作时,都会在页面中定位最新的 DOM 元素。在下面的代码片段中,底层 DOM 元素将被定位两次,一次在每个操作之前。这意味着如果 DOM 在两次调用之间由于重新渲染而发生变化,则将使用与定位器对应的新元素。

Every time a locator is used for an action, an up-to-date DOM element is located in the page. In the snippet below, the underlying DOM element will be located twice, once prior to every action. This means that if the DOM changes in between the calls due to re-render, the new element corresponding to the locator will be used.

const locator = page.getByRole('button', { name: 'Sign in' });

await locator.hover();
await locator.click();

请注意,创建定位器的所有方法(例如 page.getByLabel())也可用于 定位器FrameLocator 类,因此你可以链接它们并迭代缩小定位器范围。

Note that all methods that create a locator, such as page.getByLabel(), are also available on the Locator and FrameLocator classes, so you can chain them and iteratively narrow down your locator.

const locator = page
.frameLocator('#my-frame')
.getByRole('button', { name: 'Sign in' });

await locator.click();

按角色定位

Locate by role

page.getByRole() 定位器反映了用户和辅助技术如何感知页面,例如某个元素是按钮还是复选框。按角色定位时,通常还应该传递可访问的名称,以便定位器精确定位到确切的元素。

The page.getByRole() locator reflects how users and assistive technology perceive the page, for example whether some element is a button or a checkbox. When locating by role, you should usually pass the accessible name as well, so that the locator pinpoints the exact element.

例如,考虑以下 DOM 结构。

For example, consider the following DOM structure.

http://localhost:3000

Sign up


<h3>Sign up</h3>
<label>
<input type="checkbox" /> Subscribe
</label>
<br/>
<button>Submit</button>

你可以通过其隐含角色来定位每个元素:

You can locate each element by its implicit role:

await expect(page.getByRole('heading', { name: 'Sign up' })).toBeVisible();

await page.getByRole('checkbox', { name: 'Subscribe' }).check();

await page.getByRole('button', { name: /submit/i }).click();

角色定位器包括 按钮、复选框、标题、链接、列表、表格等等 并遵循 ARIA 角色ARIA 属性可访问的名称 的 W3C 规范。请注意,许多 html 元素(例如 <button>)都有一个由角色定位器识别的 隐式定义的角色

Role locators include buttons, checkboxes, headings, links, lists, tables, and many more and follow W3C specifications for ARIA role, ARIA attributes and accessible name. Note that many html elements like <button> have an implicitly defined role that is recognized by the role locator.

请注意,角色定位器不会取代可访问性审核和一致性测试,而是提供有关 ARIA 指南的早期反馈。

Note that role locators do not replace accessibility audits and conformance tests, but rather give early feedback about the ARIA guidelines.

何时使用角色定位器

我们建议优先考虑角色定位器来定位元素,因为这是最接近用户和辅助技术感知页面的方式。

We recommend prioritizing role locators to locate elements, as it is the closest way to how users and assistive technology perceive the page.

按标签定位

Locate by label

大多数表单控件通常都有专用标签,可以方便地用于与表单交互。在这种情况下,你可以使用 page.getByLabel() 通过其关联标签来定位该控件。

Most form controls usually have dedicated labels that could be conveniently used to interact with the form. In this case, you can locate the control by its associated label using page.getByLabel().

例如,考虑以下 DOM 结构。

For example, consider the following DOM structure.

http://localhost:3000
<label>Password <input type="password" /></label>

你可以在通过标签文本找到它后填充输入:

You can fill the input after locating it by the label text:

await page.getByLabel('Password').fill('secret');
何时使用标签定位器

定位表单字段时使用此定位器。

Use this locator when locating form fields.

通过占位符定位

Locate by placeholder

输入可能有一个占位符属性来提示用户应该输入什么值。你可以使用 page.getByPlaceholder() 找到这样的输入。

Inputs may have a placeholder attribute to hint to the user what value should be entered. You can locate such an input using page.getByPlaceholder().

例如,考虑以下 DOM 结构。

For example, consider the following DOM structure.

http://localhost:3000
<input type="email" placeholder="name@example.com" />

你可以在通过占位符文本找到输入后填充输入:

You can fill the input after locating it by the placeholder text:

await page
.getByPlaceholder('name@example.com')
.fill('playwright@microsoft.com');
何时使用占位符定位器

查找没有标签但有占位符文本的表单元素时,请使用此定位器。

Use this locator when locating form elements that do not have labels but do have placeholder texts.

通过文本定位

Locate by text

通过元素包含的文本查找元素。使用 page.getByText() 时,你可以通过子字符串、精确字符串或正则表达式进行匹配。

Find an element by the text it contains. You can match by a substring, exact string, or a regular expression when using page.getByText().

例如,考虑以下 DOM 结构。

For example, consider the following DOM structure.

http://localhost:3000
Welcome, John
<span>Welcome, John</span>

你可以通过元素包含的文本来定位该元素:

You can locate the element by the text it contains:

await expect(page.getByText('Welcome, John')).toBeVisible();

设置精确匹配:

Set an exact match:

await expect(page.getByText('Welcome, John', { exact: true })).toBeVisible();

与正则表达式匹配:

Match with a regular expression:

await expect(page.getByText(/welcome, [A-Za-z]+$/i)).toBeVisible();
注意

按文本匹配始终会标准化空格,即使是完全匹配也是如此。例如,它将多个空格变成一个,将换行符变成空格,并忽略前导和尾随空白。

Matching by text always normalizes whitespace, even with exact match. For example, it turns multiple spaces into one, turns line breaks into spaces and ignores leading and trailing whitespace.

何时使用文本定位器

我们建议使用文本定位器来查找非交互元素,如 divspanp 等。对于交互元素,如 buttonainput 等,请使用 角色定位器

We recommend using text locators to find non interactive elements like div, span, p, etc. For interactive elements like button, a, input, etc. use role locators.

你还可以使用 按文本过滤,这在尝试查找列表中的特定项目时非常有用。

You can also filter by text which can be useful when trying to find a particular item in a list.

通过替代文本定位

Locate by alt text

所有图片都应具有描述图片的 alt 属性。你可以使用 page.getByAltText() 根据替代文本定位图片。

All images should have an alt attribute that describes the image. You can locate an image based on the text alternative using page.getByAltText().

例如,考虑以下 DOM 结构。

For example, consider the following DOM structure.

http://localhost:3000
playwright logo
<img alt="playwright logo" src="/img/playwright-logo.svg" width="100" />

你可以通过文本替代找到图片后单击该图片:

You can click on the image after locating it by the text alternative:

await page.getByAltText('playwright logo').click();
何时使用替代定位器

当你的元素支持替代文本(例如 imgarea 元素)时,请使用此定位器。

Use this locator when your element supports alt text such as img and area elements.

按标题定位

Locate by title

使用 page.getByTitle() 查找具有匹配标题属性的元素。

Locate an element with a matching title attribute using page.getByTitle().

例如,考虑以下 DOM 结构。

For example, consider the following DOM structure.

http://localhost:3000
25 issues
<span title='Issues count'>25 issues</span>

你可以通过标题文本找到问题后查看问题数:

You can check the issues count after locating it by the title text:

await expect(page.getByTitle('Issues count')).toHaveText('25 issues');
何时使用标题定位器

当你的元素具有 title 属性时,请使用此定位器。

Use this locator when your element has the title attribute.

通过测试 id 定位

Locate by test id

通过测试 ID 进行测试是最具弹性的测试方式,因为即使属性的文本或角色发生更改,测试仍然会通过。QA 和开发者应定义显式测试 ID 并使用 page.getByTestId() 查询它们。然而,通过测试 ID 进行的测试并不是面向用户的。如果角色或文本值对你很重要,请考虑使用面向用户的定位器,例如 role文本定位器

Testing by test ids is the most resilient way of testing as even if your text or role of the attribute changes the test will still pass. QA's and developers should define explicit test ids and query them with page.getByTestId(). However testing by test ids is not user facing. If the role or text value is important to you then consider using user facing locators such as role and text locators.

例如,考虑以下 DOM 结构。

For example, consider the following DOM structure.

http://localhost:3000
<button data-testid="directions">Itinéraire</button>

你可以通过元素的测试 ID 来定位该元素:

You can locate the element by its test id:

await page.getByTestId('directions').click();
何时使用 testid 定位器

当你选择使用测试 ID 方法或无法通过 roletext 定位时,你也可以使用测试 ID。

You can also use test ids when you choose to use the test id methodology or when you can't locate by role or text.

设置自定义测试 id 属性

Set a custom test id attribute

默认情况下,page.getByTestId() 将根据 data-testid 属性定位元素,但你可以在测试配置中或通过调用 selectors.setTestIdAttribute()

By default, page.getByTestId() will locate elements based on the data-testid attribute, but you can configure it in your test config or by calling selectors.setTestIdAttribute().

设置测试 ID 以在测试中使用自定义数据属性。

Set the test id to use a custom data attribute for your tests.

playwright.config.ts
import { defineConfig } from '@playwright/test';

export default defineConfig({
use: {
testIdAttribute: 'data-pw'
}
});

在你的 html 中,你现在可以使用 data-pw 作为测试 ID,而不是默认的 data-testid

In your html you can now use data-pw as your test id instead of the default data-testid.

http://localhost:3000
<button data-pw="directions">Itinéraire</button>

然后像平常一样找到该元素:

And then locate the element as you would normally do:

await page.getByTestId('directions').click();

通过 CSS 或 XPath 定位

Locate by CSS or XPath

如果你绝对必须使用 CSS 或 XPath 定位器,则可以使用 page.locator() 创建一个定位器,该定位器采用一个描述如何在页面中查找元素的选择器。Playwright 支持 CSS 和 XPath 选择器,如果你省略 css=xpath= 前缀,则会自动检测它们。

If you absolutely must use CSS or XPath locators, you can use page.locator() to create a locator that takes a selector describing how to find an element in the page. Playwright supports CSS and XPath selectors, and auto-detects them if you omit css= or xpath= prefix.

await page.locator('css=button').click();
await page.locator('xpath=//button').click();

await page.locator('button').click();
await page.locator('//button').click();

XPath 和 CSS 选择器可以绑定到 DOM 结构或实现。当 DOM 结构发生变化时,这些选择器可能会中断。下面的长 CSS 或 XPath 链是导致测试不稳定的不良实践的示例:

XPath and CSS selectors can be tied to the DOM structure or implementation. These selectors can break when the DOM structure changes. Long CSS or XPath chains below are an example of a bad practice that leads to unstable tests:

await page.locator(
'#tsf > div:nth-child(2) > div.A8SBwf > div.RNNXgb > div > div.a4bIc > input'
).click();

await page
.locator('//*[@id="tsf"]/div[2]/div[1]/div[1]/div/div[2]/input')
.click();
何时使用这个

不建议使用 CSS 和 XPath,因为 DOM 经常会发生变化,从而导致非弹性测试。相反,尝试使用测试 ID 找到一个接近用户感知页面的定位器,例如 角色定位器定义明确的测试契约

CSS and XPath are not recommended as the DOM can often change leading to non resilient tests. Instead, try to come up with a locator that is close to how the user perceives the page such as role locators or define an explicit testing contract using test ids.

定位在 Shadow DOM 中

Locate in Shadow DOM

默认情况下,Playwright 中的所有定位器都适用于 Shadow DOM 中的元素。例外情况是:

All locators in Playwright by default work with elements in Shadow DOM. The exceptions are:

请考虑以下带有自定义 Web 组件的示例:

Consider the following example with a custom web component:

<x-details role=button aria-expanded=true aria-controls=inner-details>
<div>Title</div>
#shadow-root
<div id=inner-details>Details</div>
</x-details>

你可以采用与影子根根本不存在相同的方式进行定位。

You can locate in the same way as if the shadow root was not present at all.

要单击 <div>Details</div>

To click <div>Details</div>:

await page.getByText('Details').click();
<x-details role=button aria-expanded=true aria-controls=inner-details>
<div>Title</div>
#shadow-root
<div id=inner-details>Details</div>
</x-details>

要单击 <x-details>

To click <x-details>:

await page.locator('x-details', { hasText: 'Details' }).click();
<x-details role=button aria-expanded=true aria-controls=inner-details>
<div>Title</div>
#shadow-root
<div id=inner-details>Details</div>
</x-details>

要确保 <x-details> 包含文本 "细节":

To ensure that <x-details> contains the text "Details":

await expect(page.locator('x-details')).toContainText('Details');

过滤定位器

Filtering Locators

考虑以下 DOM 结构,我们希望单击第二个产品卡的购买按钮。我们有几种选择来过滤定位器以获得正确的定位器。

Consider the following DOM structure where we want to click on the buy button of the second product card. We have a few options in order to filter the locators to get the right one.

http://localhost:3000
  • Product 1

  • Product 2

<ul>
<li>
<h3>Product 1</h3>
<button>Add to cart</button>
</li>
<li>
<h3>Product 2</h3>
<button>Add to cart</button>
</li>
</ul>

按文本过滤

Filter by text

可以使用 locator.filter() 方法按文本过滤定位器。它将在元素内部的某个位置(可能在后代元素中)搜索特定字符串,不区分大小写。你还可以传递正则表达式。

Locators can be filtered by text with the locator.filter() method. It will search for a particular string somewhere inside the element, possibly in a descendant element, case-insensitively. You can also pass a regular expression.

await page
.getByRole('listitem')
.filter({ hasText: 'Product 2' })
.getByRole('button', { name: 'Add to cart' })
.click();

使用正则表达式:

Use a regular expression:

await page
.getByRole('listitem')
.filter({ hasText: /Product 2/ })
.getByRole('button', { name: 'Add to cart' })
.click();

通过不包含文本进行过滤

Filter by not having text

或者,通过不包含文本进行过滤:

Alternatively, filter by not having text:

// 5 in-stock items
await expect(page.getByRole('listitem').filter({ hasNotText: 'Out of stock' })).toHaveCount(5);

按子级/后代过滤

Filter by child/descendant

定位器支持仅选择具有或不具有与另一个定位器匹配的后代的元素的选项。因此,你可以按任何其他定位器(例如 locator.getByRole()locator.getByTestId()locator.getByText() 等)进行过滤。

Locators support an option to only select elements that have or have not a descendant matching another locator. You can therefore filter by any other locator such as a locator.getByRole(), locator.getByTestId(), locator.getByText() etc.

http://localhost:3000
  • Product 1

  • Product 2

<ul>
<li>
<h3>Product 1</h3>
<button>Add to cart</button>
</li>
<li>
<h3>Product 2</h3>
<button>Add to cart</button>
</li>
</ul>
await page
.getByRole('listitem')
.filter({ has: page.getByRole('heading', { name: 'Product 2' }) })
.getByRole('button', { name: 'Add to cart' })
.click();

我们还可以断言产品卡以确保只有一张:

We can also assert the product card to make sure there is only one:

await expect(page
.getByRole('listitem')
.filter({ has: page.getByRole('heading', { name: 'Product 2' }) }))
.toHaveCount(1);

过滤定位器必须相对于原始定位器,并且从原始定位器匹配开始查询,而不是从文档根开始。因此,以下内容将不起作用,因为过滤定位器从原始定位器匹配的 <li> 列表项之外的 <ul> 列表元素开始匹配:

The filtering locator must be relative to the original locator and is queried starting with the original locator match, not the document root. Therefore, the following will not work, because the filtering locator starts matching from the <ul> list element that is outside of the <li> list item matched by the original locator:

// ✖ WRONG
await expect(page
.getByRole('listitem')
.filter({ has: page.getByRole('list').getByText('Product 2') }))
.toHaveCount(1);

按没有子级/后代进行过滤

Filter by not having child/descendant

我们还可以通过内部没有匹配元素来进行过滤。

We can also filter by not having a matching element inside.

await expect(page
.getByRole('listitem')
.filter({ hasNot: page.getByText('Product 2') }))
.toHaveCount(1);

请注意,内部定位器是从外部定位器开始匹配的,而不是从文档根开始匹配。

Note that the inner locator is matched starting from the outer one, not from the document root.

定位器运算符

Locator operators

定位器内部匹配

Matching inside a locator

你可以链接创建定位器的方法(例如 page.getByText()locator.getByRole()),以将搜索范围缩小到页面的特定部分。

You can chain methods that create a locator, like page.getByText() or locator.getByRole(), to narrow down the search to a particular part of the page.

在本例中,我们首先通过定位其角色 listitem 来创建一个名为 Product 的定位器。然后我们按文本进行过滤。我们可以再次使用产品定位器来获取按钮的角色并单击它,然后使用断言来确保只有一个带有文本 "产品 2" 的产品。

In this example we first create a locator called product by locating its role of listitem. We then filter by text. We can use the product locator again to get by role of button and click it and then use an assertion to make sure there is only one product with the text "Product 2".

const product = page.getByRole('listitem').filter({ hasText: 'Product 2' });

await product.getByRole('button', { name: 'Add to cart' }).click();

await expect(product).toHaveCount(1);

你还可以将两个定位器链接在一起,例如在特定对话框中查找 "保存" 按钮:

You can also chain two locators together, for example to find a "Save" button inside a particular dialog:

const saveButton = page.getByRole('button', { name: 'Save' });
// ...
const dialog = page.getByTestId('settings-dialog');
await dialog.locator(saveButton).click();

同时匹配两个定位器

Matching two locators simultaneously

方法 locator.and() 通过匹配附加定位器来缩小现有定位器的范围。例如,你可以组合 page.getByRole()page.getByTitle() 以按角色和头衔进行匹配。

Method locator.and() narrows down an existing locator by matching an additional locator. For example, you can combine page.getByRole() and page.getByTitle() to match by both role and title.

const button = page.getByRole('button').and(page.getByTitle('Subscribe'));

匹配两个替代定位器之一

Matching one of the two alternative locators

如果你想要定位两个或多个元素之一,并且你不知道它将是哪一个,请使用 locator.or() 创建一个与所有替代项相匹配的定位器。

If you'd like to target one of the two or more elements, and you don't know which one it will be, use locator.or() to create a locator that matches all of the alternatives.

例如,考虑这样一个场景:你想要单击 "新邮件" 按钮,但有时会显示安全设置对话框。在这种情况下,你可以等待 "新邮件" 按钮或对话框并进行相应操作。

For example, consider a scenario where you'd like to click on a "New email" button, but sometimes a security settings dialog shows up instead. In this case, you can wait for either a "New email" button, or a dialog and act accordingly.

注意

如果屏幕上同时出现 "新邮件" 按钮和安全对话框,则 "or" 定位器将匹配它们,可能会抛出 "严格模式违规" 错误。在这种情况下,你可以使用 locator.first() 来仅匹配其中一个。

If both "New email" button and security dialog appear on screen, the "or" locator will match both of them, possibly throwing the "strict mode violation" error. In this case, you can use locator.first() to only match one of them.

const newEmail = page.getByRole('button', { name: 'New' });
const dialog = page.getByText('Confirm security settings');
await expect(newEmail.or(dialog).first()).toBeVisible();
if (await dialog.isVisible())
await page.getByRole('button', { name: 'Dismiss' }).click();
await newEmail.click();

仅匹配可见元素

Matching only visible elements

注意

通常最好找到一个 更可靠的方式 来唯一标识该元素,而不是检查可见性。

It's usually better to find a more reliable way to uniquely identify the element instead of checking the visibility.

考虑一个带有两个按钮的页面,第一个按钮不可见,第二个按钮为 visible

Consider a page with two buttons, the first invisible and the second visible.

<button style='display: none'>Invisible</button>
<button>Visible</button>
  • 这将找到两个按钮并抛出 strictness 违规错误:

    This will find both buttons and throw a strictness violation error:

    await page.locator('button').click();
  • 这只会找到第二个按钮,因为它是可见的,然后单击它。

    This will only find a second button, because it is visible, and then click it.

    await page.locator('button').locator('visible=true').click();

列表

Lists

计算列表中的项目数

Count items in a list

你可以断言定位器以计算列表中的项目数。

You can assert locators in order to count the items in a list.

例如,考虑以下 DOM 结构:

For example, consider the following DOM structure:

http://localhost:3000
  • apple
  • banana
  • orange
<ul>
<li>apple</li>
<li>banana</li>
<li>orange</li>
</ul>

使用 count 断言确保列表有 3 个项目。

Use the count assertion to ensure that the list has 3 items.

await expect(page.getByRole('listitem')).toHaveCount(3);

断言列表中的所有文本

Assert all text in a list

你可以断言定位器以查找列表中的所有文本。

You can assert locators in order to find all the text in a list.

例如,考虑以下 DOM 结构:

For example, consider the following DOM structure:

http://localhost:3000
  • apple
  • banana
  • orange
<ul>
<li>apple</li>
<li>banana</li>
<li>orange</li>
</ul>

使用 expect(locator).toHaveText() 确保列表包含文本 "apple"、"banana" 和 "orange"。

Use expect(locator).toHaveText() to ensure that the list has the text "apple", "banana" and "orange".

await expect(page
.getByRole('listitem'))
.toHaveText(['apple', 'banana', 'orange']);

获取特定项目

Get a specific item

有多种方法可以获取列表中的特定项目。

There are many ways to get a specific item in a list.

通过文本获取

Get by text

使用 page.getByText() 方法通过文本内容找到列表中的元素,然后单击它。

Use the page.getByText() method to locate an element in a list by its text content and then click on it.

例如,考虑以下 DOM 结构:

For example, consider the following DOM structure:

http://localhost:3000
  • apple
  • banana
  • orange
<ul>
<li>apple</li>
<li>banana</li>
<li>orange</li>
</ul>

通过文本内容找到项目并单击它。

Locate an item by its text content and click it.

await page.getByText('orange').click();
http://localhost:3000
  • apple
  • banana
  • orange
<ul>
<li>apple</li>
<li>banana</li>
<li>orange</li>
</ul>

按文本过滤

Filter by text

使用 locator.filter() 查找列表中的特定项目。

Use the locator.filter() to locate a specific item in a list.

例如,考虑以下 DOM 结构:

For example, consider the following DOM structure:

http://localhost:3000
  • apple
  • banana
  • orange
<ul>
<li>apple</li>
<li>banana</li>
<li>orange</li>
</ul>

按 "listitem" 的角色找到一个项目,然后按 "orange" 的文本过滤,然后单击它。

Locate an item by the role of "listitem" and then filter by the text of "orange" and then click it.

await page
.getByRole('listitem')
.filter({ hasText: 'orange' })
.click();

通过测试 id 获取

Get by test id

使用 page.getByTestId() 方法定位列表中的元素。如果你还没有测试 ID,则可能需要修改 html 并添加测试 ID。

Use the page.getByTestId() method to locate an element in a list. You may need to modify the html and add a test id if you don't already have a test id.

例如,考虑以下 DOM 结构:

For example, consider the following DOM structure:

http://localhost:3000
  • apple
  • banana
  • orange
<ul>
<li data-testid='apple'>apple</li>
<li data-testid='banana'>banana</li>
<li data-testid='orange'>orange</li>
</ul>

通过测试 ID "orange" 找到一个项目,然后单击它。

Locate an item by it's test id of "orange" and then click it.

await page.getByTestId('orange').click();

获取第 n 项

Get by nth item

如果你有一个包含相同元素的列表,并且区分它们的唯一方法是顺序,则可以从具有 locator.first()locator.last()locator.nth() 的列表中选择特定元素。

If you have a list of identical elements, and the only way to distinguish between them is the order, you can choose a specific element from a list with locator.first(), locator.last() or locator.nth().

const banana = await page.getByRole('listitem').nth(1);

但是,请谨慎使用此方法。很多时候,页面可能会发生变化,并且定位器将指向与你期望的完全不同的元素。相反,尝试想出一个能够通过 严格标准 的独特定位器。

However, use this method with caution. Often times, the page might change, and the locator will point to a completely different element from the one you expected. Instead, try to come up with a unique locator that will pass the strictness criteria.

链接过滤器

Chaining filters

当你有各种相似的元素时,你可以使用 locator.filter() 方法来选择正确的元素。你还可以链接多个过滤器来缩小选择范围。

When you have elements with various similarities, you can use the locator.filter() method to select the right one. You can also chain multiple filters to narrow down the selection.

例如,考虑以下 DOM 结构:

For example, consider the following DOM structure:

http://localhost:3000
  • John
  • Mary
  • John
  • Mary
<ul>
<li>
<div>John</div>
<div><button>Say hello</button></div>
</li>
<li>
<div>Mary</div>
<div><button>Say hello</button></div>
</li>
<li>
<div>John</div>
<div><button>Say goodbye</button></div>
</li>
<li>
<div>Mary</div>
<div><button>Say goodbye</button></div>
</li>
</ul>

要截取 "Mary" 和 "说再见" 行的屏幕截图:

To take a screenshot of the row with "Mary" and "Say goodbye":

const rowLocator = page.getByRole('listitem');

await rowLocator
.filter({ hasText: 'Mary' })
.filter({ has: page.getByRole('button', { name: 'Say goodbye' }) })
.screenshot({ path: 'screenshot.png' });

现在,你的项目根目录中应该有一个 "screenshot.png" 文件。

You should now have a "screenshot.png" file in your project's root directory.

罕见用例

Rare use cases

对列表中的每个元素执行一些操作

Do something with each element in the list

迭代元素:

Iterate elements:

for (const row of await page.getByRole('listitem').all())
console.log(await row.textContent());

使用常规 for 循环进行迭代:

Iterate using regular for loop:

const rows = page.getByRole('listitem');
const count = await rows.count();
for (let i = 0; i < count; ++i)
console.log(await rows.nth(i).textContent());

在页面中进行评价

Evaluate in the page

locator.evaluateAll() 里面的代码在页面中运行,你可以在那里调用任何 DOM api。

The code inside locator.evaluateAll() runs in the page, you can call any DOM apis there.

const rows = page.getByRole('listitem');
const texts = await rows.evaluateAll(
list => list.map(element => element.textContent));

严格

Strictness

定位器是严格的。这意味着如果多个元素匹配,则暗示某个目标 DOM 元素的定位器上的所有操作都将引发异常。例如,如果 DOM 中有多个按钮,则以下调用会抛出异常:

Locators are strict. This means that all operations on locators that imply some target DOM element will throw an exception if more than one element matches. For example, the following call throws if there are several buttons in the DOM:

如果超过一个则抛出错误

Throws an error if more than one

await page.getByRole('button').click();

另一方面,Playwright 可以理解你何时执行多元素操作,因此当定位器解析为多个元素时,以下调用可以正常工作。

On the other hand, Playwright understands when you perform a multiple-element operation, so the following call works perfectly fine when the locator resolves to multiple elements.

适用于多个元素

Works fine with multiple elements

await page.getByRole('button').count();

你可以通过 locator.first()locator.last()locator.nth() 告诉 Playwright 当多个元素匹配时使用哪个元素,从而明确选择退出严格性检查。不建议使用这些方法,因为当你的页面更改时,Playwright 可能会单击你不想要的元素。相反,请遵循上述最佳实践来创建唯一标识目标元素的定位器。

You can explicitly opt-out from strictness check by telling Playwright which element to use when multiple elements match, through locator.first(), locator.last(), and locator.nth(). These methods are not recommended because when your page changes, Playwright may click on an element you did not intend. Instead, follow best practices above to create a locator that uniquely identifies the target element.

更多定位器

More Locators

对于不太常用的定位器,请查看 其他定位器 指南。

For less commonly used locators, look at the other locators guide.