可扩展性

自定义选择器引擎

Playwright 支持通过 selectors.register() 注册的自定义选择器引擎。

选择器引擎应具有以下属性

• query 函数：用于查询相对于 root 匹配 selector 的第一个元素。
• queryAll 函数：用于查询相对于 root 匹配 selector 的所有元素。

默认情况下，引擎直接在帧的 JavaScript 上下文运行，例如，可以调用应用程序定义的函数。要将引擎与帧中的任何 JavaScript 隔离，但仍允许访问 DOM，请使用 {contentScript: true} 选项注册引擎。内容脚本引擎更安全，因为它受到保护，免受对全局对象的任何篡改，例如修改 Node.prototype 方法。所有内置选择器引擎都作为内容脚本运行。请注意，当引擎与其他自定义引擎一起使用时，不能保证作为内容脚本运行。

必须在创建页面之前注册选择器。

注册基于标签名查询元素的选择器引擎的示例

同步

tag_selector = """
    // Must evaluate to a selector engine instance.
    {
      // Returns the first element matching given selector in the root's subtree.
      query(root, selector) {
        return root.querySelector(selector);
      },

      // Returns all elements matching given selector in the root's subtree.
      queryAll(root, selector) {
        return Array.from(root.querySelectorAll(selector));
      }
    }"""

# register the engine. selectors will be prefixed with "tag=".
playwright.selectors.register("tag", tag_selector)

# now we can use "tag=" selectors.
button = page.locator("tag=button")
button.click()

# we can combine it with built-in locators.
page.locator("tag=div").get_by_text("click me").click()

# we can use it in any methods supporting selectors.
button_count = page.locator("tag=button").count()

异步

tag_selector = """
    // Must evaluate to a selector engine instance.
    {
      // Returns the first element matching given selector in the root's subtree.
      query(root, selector) {
        return root.querySelector(selector);
      },

      // Returns all elements matching given selector in the root's subtree.
      queryAll(root, selector) {
        return Array.from(root.querySelectorAll(selector));
      }
    }"""

# register the engine. selectors will be prefixed with "tag=".
await playwright.selectors.register("tag", tag_selector)

# now we can use "tag=" selectors.
button = page.locator("tag=button")
await button.click()

# we can combine it with built-in locators.
await page.locator("tag=div").get_by_text("click me").click()

# we can use it in any methods supporting selectors.
button_count = await page.locator("tag=button").count()