Update api.md

official/api.md

@@ -576,10 +576,9 @@ const browser = await puppeteer.launch({executablePath: revisionInfo.executableP
 
 * extends: [`EventEmitter`](https://nodejs.org/api/events.html#events_class_eventemitter)
 
-当 Puppeteer 连接到一个 Chromium 实例的时候会通过 [`puppeteer.launch`](#puppeteerlaunchoptions) 或 [`puppeteer.connect`](#puppeteerconnectoptions) 创建一个 Browser 对象。
-
-下面是使用 ```Browser``` 创建 ```Page``` 的例子
+A Browser is created when Puppeteer connects to a Chromium instance, either through [`puppeteer.launch`](#puppeteerlaunchoptions) or [`puppeteer.connect`](#puppeteerconnectoptions).
 
+An example of using a [Browser] to create a [Page]:
 ```js
 const puppeteer = require('puppeteer');
 
@@ -590,119 +589,118 @@ puppeteer.launch().then(async browser => {
 });
 ```
 
-一个断开连接和重连到 [Browser] 的例子：
-
+An example of disconnecting from and reconnecting to a [Browser]:
 ```js
 const puppeteer = require('puppeteer');
 
 puppeteer.launch().then(async browser => {
-  // 存储节点以便能重新连接到 Chromium
+  // Store the endpoint to be able to reconnect to Chromium
   const browserWSEndpoint = browser.wsEndpoint();
-  // 从 Chromium 断开和 puppeteer 的连接
+  // Disconnect puppeteer from Chromium
   browser.disconnect();
 
-  // 使用节点来重新建立连接
+  // Use the endpoint to reestablish a connection
   const browser2 = await puppeteer.connect({browserWSEndpoint});
-  // 关闭 Chromium
+  // Close Chromium
   await browser2.close();
 });
 ```
-
 #### event: 'disconnected'
-当 Puppeteer 从 Chromium 实例断开连接时被触发。原因可能如下：
-
-- Chromium 关闭或崩溃
-- 调用[`browser.disconnect`](#browserdisconnect) 方法
+Emitted when Puppeteer gets disconnected from the Chromium instance. This might happen because of one of the following:
+- Chromium is closed or crashed
+- The [`browser.disconnect`](#browserdisconnect) method was called
 
 #### event: 'targetchanged'
 - <[Target]>
 
-当目标的 url 改变时被触发
+Emitted when the url of a target changes.
 
-> **注意** 这包括匿名浏览器上下文中的目标更改。
+> **NOTE** This includes target changes in incognito browser contexts.
 
 
 #### event: 'targetcreated'
 - <[Target]>
 
-当目标被创建时被触发，例如当通过 [`window.open`](https://developer.mozilla.org/en-US/docs/Web/API/Window/open) 或 [`browser.newPage`](#browsernewpage) 打开一个新的页面。
+Emitted when a target is created, for example when a new page is opened by [`window.open`](https://developer.mozilla.org/en-US/docs/Web/API/Window/open) or [`browser.newPage`](#browsernewpage).
 
-> **注意** 这包括匿名浏览器上下文中的目标创建。
+> **NOTE** This includes target creations in incognito browser contexts.
 
 #### event: 'targetdestroyed'
 - <[Target]>
 
-当目标被销毁时被触发，例如当一个页面被关闭时。
+Emitted when a target is destroyed, for example when a page is closed.
 
-> **注意** 这包括匿名浏览器上下文中的目标销毁。
+> **NOTE** This includes target destructions in incognito browser contexts.
 
 #### browser.browserContexts()
 - returns: <[Array]<[BrowserContext]>>
 
-返回一个包含所有打开的浏览器上下文的数组。在新创建的浏览器中，这将返回 [BrowserContext] 的单一实例。
+Returns an array of all open browser contexts. In a newly created browser, this will return
+a single instance of [BrowserContext].
 
 #### browser.close()
 - returns: <[Promise]>
 
-关闭 Chromium 及其所有页面(如果页面被打开的话)。[Browser] 对象本身被认为是处理过的并不能再被使用。
+Closes Chromium and all of its pages (if any were opened). The [Browser] object itself is considered to be disposed and cannot be used anymore.
 
 #### browser.createIncognitoBrowserContext()
 - returns: <[Promise]<[BrowserContext]>>
 
-创建一个匿名的浏览器上下文。这将不会与其他浏览器上下文分享 cookies/cache。
+Creates a new incognito browser context. This won't share cookies/cache with other browser contexts.
 
 ```js
 const browser = await puppeteer.launch();
-// 创建一个匿名的浏览器上下文
+// Create a new incognito browser context.
 const context = await browser.createIncognitoBrowserContext();
-// 在一个原生的上下文中创建一个新页面
+// Create a new page in a pristine context.
 const page = await context.newPage();
-// 做一些事情
+// Do stuff
 await page.goto('https://example.com');
 ```
 
 #### browser.defaultBrowserContext()
 - returns: <[BrowserContext]>
 
-返回一个默认的浏览器上下文。这个上下文不能被关闭。
+Returns the default browser context. The default browser context can not be closed.
 
 #### browser.disconnect()
 
-断开 Puppeteer 和浏览器的连接，但 Chromium 进程仍然在运行。在调用 ```disconnect``` 之后，[Browser] 对象本身被认为是处理过的并不能再被使用。
+Disconnects Puppeteer from the browser, but leaves the Chromium process running. After calling `disconnect`, the [Browser] object is considered disposed and cannot be used anymore.
 
 #### browser.newPage()
 - returns: <[Promise]<[Page]>>
 
-返回一个新的 [Page] 对象。[Page] 在一个默认的浏览器上下文中被创建。
+Promise which resolves to a new [Page] object. The [Page] is created in a default browser context.
 
 #### browser.pages()
-- returns: <[Promise]<[Array]<[Page]>>> 返回一个包含所有打开的页面的数组。页面不可见的，比如 `"background_page"` 将不会列在这。不过你可以通过 [target.page()](#targetpage) 找到它们。
+- returns: <[Promise]<[Array]<[Page]>>> Promise which resolves to an array of all open pages. Non visible pages, such as `"background_page"`, will not be listed here. You can find them using [target.page()](#targetpage).
 
-返回一个浏览器中所有页面的数组。 在多个浏览器上下文的情况下，
-该方法将返回一个包含所有浏览器上下文中所有页面的数组。
+An array of all pages inside the Browser. In case of multiple browser contexts,
+the method will return an array with all the pages in all browser contexts.
 
 #### browser.process()
-- returns: <?[ChildProcess]> 产生浏览器的进程。如果浏览器实例是由 [`puppeteer.connect`](#puppeteerconnectoptions) 方法创建的则返回null。
+- returns: <?[ChildProcess]> Spawned browser process. Returns `null` if the browser instance was created with [`puppeteer.connect`](#puppeteerconnectoptions) method.
 
 #### browser.target()
 - returns: <[Target]>
 
-返回浏览器相关的目标对象。
+A target associated with the browser.
 
 #### browser.targets()
 - returns: <[Array]<[Target]>>
 
-浏览器内所有活动目标组成的数组。在多个浏览器上下文的情况下，该方法将返回一个包含所有浏览器上下文中的所有目标的数组。
+An array of all active targets inside the Browser. In case of multiple browser contexts,
+the method will return an array with all the targets in all browser contexts.
 
 #### browser.userAgent()
-- returns: <[Promise]<[string]>> 返回浏览器原始的 user-agent
+- returns: <[Promise]<[string]>> Promise which resolves to the browser's original user agent.
 
-> **注意** 页面可以使用 [page.setUserAgent](#pagesetuseragentuseragent) 覆盖浏览器的 user-agent
+> **NOTE** Pages can override browser user agent with [page.setUserAgent](#pagesetuseragentuseragent)
 
 #### browser.version()
-- returns: <[Promise]<[string]>> 对于无头的 Chromium，这类似于 `HeadlessChrome/61.0.3153.0`. 对于非无头的Chromium, 这类似于 `Chrome/61.0.3153.0。`
+- returns: <[Promise]<[string]>> For headless Chromium, this is similar to `HeadlessChrome/61.0.3153.0`. For non-headless, this is similar to `Chrome/61.0.3153.0`.
 
-> **注意** browser.version() 的格式可能在未来版本的 Chromium 中发生变化。
+> **NOTE** the format of browser.version() might change with future releases of Chromium.
 
 #### browser.waitForTarget(predicate[, options])
 - `predicate` <[function]\([Target]\):[boolean]> A function to be run for every target
@@ -719,11 +717,12 @@ const newWindowTarget = await browser.waitForTarget(target => target.url() === '
 ```
 
 #### browser.wsEndpoint()
-- returns: <[string]> 返回浏览器 websocket 的地址
+- returns: <[string]> Browser websocket url.
 
-[puppeteer.connect](#puppeteerconnectoptions) 可以将浏览器 websocket 端作为一个参数。其格式为 `ws://${host}:${port}/devtools/browser/<id>`。
+Browser websocket endpoint which can be used as an argument to
+[puppeteer.connect](#puppeteerconnectoptions). The format is `ws://${host}:${port}/devtools/browser/<id>`
 
-你可以从 `http://${host}:${port}/json/version` 找到 `webSocketDebuggerUrl` 。了解更多有关 [devtools protocol](https://chromedevtools.github.io/devtools-protocol) 和 [browser endpoint](https://chromedevtools.github.io/devtools-protocol/#how-do-i-access-the-browser-target) 的信息。
+You can find the `webSocketDebuggerUrl` from `http://${host}:${port}/json/version`. Learn more about the [devtools protocol](https://chromedevtools.github.io/devtools-protocol) and the [browser endpoint](https://chromedevtools.github.io/devtools-protocol/#how-do-i-access-the-browser-target).
 
 ### class: BrowserContext
 
@@ -3488,4 +3487,4 @@ _使用 [Istanbul](https://github.com/istanbuljs) 输出一个覆盖率表格，
 [Worker]: #class-worker "Worker"
 [Accessibility]: #class-accessibility "Accessibility"
 [AXNode]: #accessibilitysnapshotoptions "AXNode"
-[ConnectionTransport]: ../lib/WebSocketTransport.js "ConnectionTransport"
+[ConnectionTransport]: ../lib/WebSocketTransport.js "ConnectionTransport"