Merge pull request #584 from 02zchen/master

Update article.md

Author: iliakan

1-js/01-getting-started/1-intro/article.md

@@ -1,12 +1,12 @@
 # An Introduction to JavaScript
 
-Let's see what's so special about JavaScript, what we can achieve with it and which other technologies play well with it.
+Let's see what's so special about JavaScript, what we can achieve with it, and which other technologies play well with it.
 
 ## What is JavaScript?
 
 *JavaScript* was initially created to *"make webpages alive"*.
 
-The programs in this language are called *scripts*. They can be written right in the HTML and execute automatically as the page loads.
+The programs in this language are called *scripts*. They can be written right in the HTML and executed automatically as the page loads.
 
 Scripts are provided and executed as a plain text. They don't need a special preparation or a compilation to run.
 
@@ -18,15 +18,15 @@ When JavaScript was created, it initially had another name: "LiveScript". But Ja
 But as it evolved, JavaScript became a fully independent language, with its own specification called [ECMAScript](http://en.wikipedia.org/wiki/ECMAScript), and now it has no relation to Java at all.
 ```
 
-At present, JavaScript can execute not only in the browser, but also on the server, or actually on any device where there exists a special program called [the JavaScript engine](https://en.wikipedia.org/wiki/JavaScript_engine).
+At present, JavaScript can not only execute in the browser, but also on the server, or actually on any device that has a special program called [the JavaScript engine](https://en.wikipedia.org/wiki/JavaScript_engine).
 
-The browser has an embedded engine, sometimes it's also called a "JavaScript virtual machine".
+The browser has an embedded engine, sometimes called a "JavaScript virtual machine".
 
 Different engines have different "codenames", for example:
 
 - [V8](https://en.wikipedia.org/wiki/V8_(JavaScript_engine)) -- in Chrome and Opera.
 - [SpiderMonkey](https://en.wikipedia.org/wiki/SpiderMonkey) -- in Firefox.
-- ...There are other codenames like "Trident", "Chakra" for different versions of IE, "ChakraCore" for Microsoft Edge, "Nitro" and "SquirrelFish" for Safari, etc.
+- ...There are other codenames like "Trident" and "Chakra" for different versions of IE, "ChakraCore" for Microsoft Edge, "Nitro" and "SquirrelFish" for Safari, etc.
 
 The terms above are good to remember, because they are used in developer articles on the internet. We'll use them too. For instance, if "a feature X is supported by V8", then it probably works in Chrome and Opera.
 
@@ -47,7 +47,7 @@ The modern JavaScript is a "safe" programming language. It does not provide low-
 
 The capabilities greatly depend on the environment that runs JavaScript. For instance, [Node.JS](https://wikipedia.org/wiki/Node.js) supports functions that allow JavaScript to read/write arbitrary files, perform network requests, etc.
 
-In-browser JavaScript can do everything related to webpage manipulation, interaction with the user and the webserver.
+In-browser JavaScript can do everything related to webpage manipulation, interaction with the user, and the webserver.
 
 For instance, in-browser JavaScript is able to: