docs(verification): nits and typos

docs/README.md

@@ -32,11 +32,10 @@
     - [Modify requests](./network.md#modify-requests)
     - [Abort requests](./network.md#abort-requests)
 1. [Scraping and verification](./verification.md)
-    - [Screenshots](./verification.md#capturing-screenshot)
+    - [Evaluating JavaScript](./verification.md#evaluating-javascript)
-    - [Evaluation](./verification.md#evaluating-javascript)
+    - [Capturing screenshot](./verification.md#capturing-screenshot)
-    - [Console messages](./verification.md#listening-console-messages)
+    - [Page events](./verification.md#page-events)
-    - [Uncaghut exceptions](./verification.md#uncaghut-exceptions)
+    - [Handling exceptions](./verification.md#handling-exceptions)
-    - [Page crashes](./verification.md#page-crashes)
 1. [Navigation and loading](./loading.md)
     - [Common scenarios](./loading.md#common-scenarios)
     - [Loading a popup](./loading.md#loading-a-popup)

docs/verification.md

@@ -1,19 +1,10 @@
 # Scraping and verification
 
-Playwright allows verifiying state of the page and catching abnormal behavior by:
-  - evaluating JavaScript code snippets in the page
-  - capturing screenshots (png or jpeg)
-  - listening console messages
-  - observing uncaghut exceptions in the page
-  - observing page crashes
-  - etc
-
 #### Contents
 - [Evaluating JavaScript](#evaluating-javascript)
 - [Capturing screenshot](#capturing-screenshot)
-- [Listening console messages](#listening-console-messages)
+- [Page events](#page-events)
-- [Uncaghut exceptions](#uncaghut-exceptions)
+- [Handling exceptions](#handling-exceptions)
-- [Page crashes](#page-crashes)
 
 <br/>
 
@@ -24,7 +15,7 @@ Execute JavaScript function in the page:
 const href = await page.evaluate(() => document.location.href);
 ```
 
-If the result is a Promise or if the function is asynchronouse eveluate will automatically wait until it's resolved:
+If the result is a Promise or if the function is asynchronous evaluate will automatically wait until it's resolved:
 ```js
 const status = await page.evaluate(async () => {
   const response = await fetch(location.href);
@@ -34,7 +25,7 @@ If the result is a Promise or if the function is asynchronouse eveluate will aut
 
 Get object handle and use it in multiple evaluations:
 ```js
-  // Create a new array in the page, wriate a reference to it in
+// Create a new array in the page, write a reference to it in
 // window.myArray and get a handle to it.
 const myArrayHandle = await page.evaluateHandle(() => {
   window.myArray = [1];
@@ -77,60 +68,81 @@ Take screenshot of the page's viewport and save it in a png file:
 ```js
 await page.screenshot({path: 'screenshot.png'});
 ```
-Capture entire scrollable area of the page:
+
+#### Variations
+
+Capture particular element:
+```js
+const elementHandle = await page.$('.header');
+await elementHandle.screenshot({ path: 'screenshot.png' });
+```
+
+Capture full page screenshot:
 ```js
 await page.screenshot({path: 'screenshot.png', fullPage: true});
 ```
-Save screenshot in an in-memory buffer (the content is base64-encoded image bytes):
+
+Capture screenshot into a Node [Buffer](https://nodejs.org/api/buffer.html#buffer_class_buffer).
 ```js
 const buffer = await page.screenshot();
 // Log the length.
-  console.log(buffer.length);
+console.log(buffer.toString('base64'));
 ```
 
 
 #### API reference
 
 - [page.screenshot([options])](./api.md#pagescreenshotoptions)
-- [Node.js Buffer](https://nodejs.org/api/buffer.html)
+- [elementHandle.screenshot([options])](./api.md#elementhandlescreenshotoptions)
 
 <br/>
 
-## Listening console messages
+## Page events
 
-Listen all console messages in a page and dump _errors_ in to the terminal:
+You can listen for various events on the `page` object. Following are just some of the examples of the events you can assert and handle:
+
+#### "`console`" - get all console messages from the page
 
 ```js
-  // Get all console messages from the page.
 page.on('console', msg => {
   // Handle only errors.
   if (msg.type() !== 'error')
     return;
   console.log(`text: "${msg.text()}"`);
 });
-
-  await page.evaluate(() => console.error('Page error message'));
 ```
-Get access to the console message arguments:
+
+#### "`dialog`" - Handle assert, confirm, prompt
+
 ```js
-  page.on('console', msg => {
+page.on('dialog', dialog => {
-    for (let i = 0; i < msg.args().length; ++i)
+  dialog.accept();
-      console.log(`${i}: ${msg.args()[i]}`);
 });
 ```
 
+#### "`popup`" - Handle assert, confirm, prompt
+
+```js
+const [popup] = await Promise.all([
+  page.waitForEvent('popup'),
+  page.click('#open')
+]);
+```
+
 #### API reference
 
-- [class: ConsoleMessage](./api.md#class-consolemessage)
+- [class: Page](./api.md#class-page)
-- [class `JSHandle`](./api.md#class-jshandle)
 - [event: 'console'](./api.md#event-console)
+- [event: 'dialog'](./api.md#event-dialog)
+- [event: 'popup'](./api.md#event-popup)
+- [class: ConsoleMessage](./api.md#class-consolemessage)
 
 <br/>
 
 
-## Uncaghut exceptions
+## Handling exceptions
 
-Listen uncaghut exceptions in the page:
+Listen uncaught exceptions in the page:
 ```js
 // Log all uncaught errors to the terminal
 page.on('pageerror', exception => {
@@ -146,19 +158,3 @@ Listen uncaghut exceptions in the page:
 - [event: 'pageerror'](./api.md#event-pageerror)
 
 <br/>
-
-## Page crashes
-
-Listen to page crashes:
-```js
-  page.on('crash', exception => {
-    console.log(`Page crashed`);
-  });
-```
-It's very unusual for page to crash but might happen if a page allocates too much memory or due to a bug in a browser.
-
-#### API reference
-
-- [event: 'crash'](./api.md#event-crash)
-
-<br/>