playwright/docs/src/events.md

---
id: events
title: "Events"
---

Playwright allows listening to various types of events happening on the web page, such as network requests, creation of child pages, dedicated workers etc. There are several ways to subscribe to such events such as waiting for events or adding or removing event listeners.

## Waiting for event

Most of the time, scripts will need to wait for a particular event to happen. Below are some of the typical event awaiting patterns.

Wait for a request with the specified url using [`method: Page.waitForRequest`]:

```js
// Start waiting for request before goto. Note no await.
const requestPromise = page.waitForRequest('**/*logo*.png');
await page.goto('https://wikipedia.org');
const request = await requestPromise;
console.log(request.url());
```

```java
// The callback lambda defines scope of the code that is expected to
// trigger request.
Request request = page.waitForRequest("**/*logo*.png", () -> {
  page.navigate("https://wikipedia.org");
});
System.out.println(request.url());
```

```python async
async with page.expect_request("**/*logo*.png") as first:
  await page.goto("https://wikipedia.org")
first_request = await first.value
print(first_request.url)
```

```python sync
with page.expect_request("**/*logo*.png") as first:
  page.goto("https://wikipedia.org")
print(first.value.url)
```

```csharp
var waitForRequestTask = page.WaitForRequestAsync("**/*logo*.png");
await page.GotoAsync("https://wikipedia.org");
var request = await waitForRequestTask;
Console.WriteLine(request.Url);
```

Wait for popup window:

```js
// Start waiting for popup before clicking. Note no await.
const popupPromise = page.waitForEvent('popup');
await page.getByText('open the popup').click();
const popup = await popupPromise;
await popup.goto('https://wikipedia.org');
```

```java
// The callback lambda defines scope of the code that is expected to
// create popup window.
Page popup = page.waitForPopup(() -> {
  page.getByText("open the popup").click();
});
popup.navigate("https://wikipedia.org");
```

```python async
async with page.expect_popup() as popup:
  await page.get_by_text("open the popup").click()
child_page = await popup.value
await child_page.goto("https://wikipedia.org")
```

```python sync
with page.expect_popup() as popup:
  page.get_by_text("open the popup").click()
popup.value.goto("https://wikipedia.org")
```

```csharp
var popup = await page.RunAndWaitForPopupAsync(async =>
{
    await page.GetByText("open the popup").ClickAsync();
});
await popup.GotoAsync("https://wikipedia.org");
```

## Adding/removing event listener

Sometimes, events happen in random time and instead of waiting for them, they need to be handled. Playwright supports traditional language mechanisms for subscribing and unsubscribing from the events:

```js
page.on('request', request => console.log(`Request sent: ${request.url()}`));
const listener = request => console.log(`Request finished: ${request.url()}`);
page.on('requestfinished', listener);
await page.goto('https://wikipedia.org');

page.off('requestfinished', listener);
await page.goto('https://www.openstreetmap.org/');
```

```java
page.onRequest(request -> System.out.println("Request sent: " + request.url()));
Consumer<Request> listener = request -> System.out.println("Request finished: " + request.url());
page.onRequestFinished(listener);
page.navigate("https://wikipedia.org");

// Remove previously added listener, each on* method has corresponding off*
page.offRequestFinished(listener);
page.navigate("https://www.openstreetmap.org/");
```

```python async
def print_request_sent(request):
  print("Request sent: " + request.url)

def print_request_finished(request):
  print("Request finished: " + request.url)

page.on("request", print_request_sent)
page.on("requestfinished", print_request_finished)
await page.goto("https://wikipedia.org")

page.remove_listener("requestfinished", print_request_finished)
await page.goto("https://www.openstreetmap.org/")
```

```python sync
def print_request_sent(request):
  print("Request sent: " + request.url)

def print_request_finished(request):
  print("Request finished: " + request.url)

page.on("request", print_request_sent)
page.on("requestfinished", print_request_finished)
page.goto("https://wikipedia.org")

page.remove_listener("requestfinished", print_request_finished)
page.goto("https://www.openstreetmap.org/")
```

```csharp
page.Request += (_, request) => Console.WriteLine("Request sent: " + request.Url);
void listener(object sender, IRequest request)
{
    Console.WriteLine("Request finished: " + request.Url);
};
page.RequestFinished += listener;
await page.GotoAsync("https://wikipedia.org");

// Remove previously added listener.
page.RequestFinished -= listener;
await page.GotoAsync("https://www.openstreetmap.org/");
```

## Adding one-off listeners
* langs: js, python, java

If a certain event needs to be handled once, there is a convenience API for that:

```js
page.once('dialog', dialog => dialog.accept("2021"));
await page.evaluate("prompt('Enter a number:')");
```

```java
page.onceDialog(dialog -> dialog.accept("2021"));
page.evaluate("prompt('Enter a number:')");
```

```python async
page.once("dialog", lambda dialog: dialog.accept("2021"))
await page.evaluate("prompt('Enter a number:')")
```

```python sync
page.once("dialog", lambda dialog: dialog.accept("2021"))
page.evaluate("prompt('Enter a number:')")
```