mirror of
https://github.com/microsoft/playwright.git
synced 2025-06-26 21:40:17 +00:00
52 lines
2.4 KiB
Markdown
52 lines
2.4 KiB
Markdown
# Extensibility
|
|
|
|
<!-- GEN:toc-top-level -->
|
|
- [Custom selector engines](#custom-selector-engines)
|
|
<!-- GEN:stop -->
|
|
|
|
## Custom selector engines
|
|
|
|
Playwright supports custom selector engines, registered with [selectors.register(name, script[, options])](api.md#selectorsregistername-script-options).
|
|
|
|
Selector engine should have the following properties:
|
|
|
|
- `create` function to create a relative selector from `root` (root is either a `Document`, `ShadowRoot` or `Element`) to a `target` element.
|
|
- `query` function to query first element matching `selector` relative to the `root`.
|
|
- `queryAll` function to query all elements matching `selector` relative to the `root`.
|
|
|
|
By default the engine is run directly in the frame's JavaScript context and, for example, can call an application-defined function. To isolate the engine from any JavaScript in the frame, but leave access to the DOM, register the engine with `{contentScript: true}` option. Content script engine is safer because it is protected from any tampering with the global objects, for example altering `Node.prototype` methods. All built-in selector engines run as content scripts. Note that running as a content script is not guaranteed when the engine is used together with other custom engines.
|
|
|
|
An example of registering selector engine that queries elements based on a tag name:
|
|
```js
|
|
// Must be a function that evaluates to a selector engine instance.
|
|
const createTagNameEngine = () => ({
|
|
// Creates a selector that matches given target when queried at the root.
|
|
// Can return undefined if unable to create one.
|
|
create(root, target) {
|
|
return root.querySelector(target.tagName) === target ? target.tagName : undefined;
|
|
},
|
|
|
|
// 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 selectors.register('tag', createTagNameEngine);
|
|
|
|
// Now we can use 'tag=' selectors.
|
|
const button = await page.$('tag=button');
|
|
|
|
// We can combine it with other selector engines using `>>` combinator.
|
|
await page.click('tag=div >> span >> "Click me"');
|
|
|
|
// We can use it in any methods supporting selectors.
|
|
const buttonCount = await page.$$eval('tag=button', buttons => buttons.length);
|
|
```
|