Merge branch 'master' of github.com:javascript-tutorial/en.javascript.info into sync-34e9cdca

Author: iliakan

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

@@ -75,7 +75,7 @@ Examples of such restrictions include:
     This limitation is, again, for the user's safety. A page from `http://anysite.com` which a user has opened must not be able to access another browser tab with the URL `http://gmail.com` and steal information from there.
 - JavaScript can easily communicate over the net to the server where the current page came from. But its ability to receive data from other sites/domains is crippled. Though possible, it requires explicit agreement (expressed in HTTP headers) from the remote side. Once again, that's a safety limitation.
 
-![](limitations.png)
+![](limitations.svg)
 
 Such limits do not exist if JavaScript is used outside of the browser, for example on a server. Modern browsers also allow plugin/extensions which may ask for extended permissions.
 
@@ -92,8 +92,7 @@ JavaScript is the only browser technology that combines these three things.
 
 That's what makes JavaScript unique. That's why it's the most widespread tool for creating browser interfaces.
 
-While planning to learn a new technology, it's beneficial to check its perspectives. So let's move on to the modern trends affecting it,  including new languages and browser abilities.
-
+That said, JavaScript also allows to create servers, mobile applications, etc.
 
 ## Languages "over" JavaScript
 

1-js/01-getting-started/1-intro/limitations.png

@@ -50,11 +50,11 @@ Open Preferences and go to the "Advanced" pane. There's a checkbox at the bottom
 
 Now `key:Cmd+Opt+C` can toggle the console. Also, note that the new top menu item named "Develop" has appeared. It has many commands and options.
 
-## Multi-line input
-
+```smart header="Multi-line input"
 Usually, when we put a line of code into the console, and then press `key:Enter`, it executes.
 
-To insert multiple lines, press `key:Shift+Enter`.
+To insert multiple lines, press `key:Shift+Enter`. This way one can enter long fragments of JavaScript code.
+```
 
 ## Summary
 

1-js/01-getting-started/1-intro/limitations.svg

@@ -1,6 +1,6 @@
 # Hello, world!
 
-This part of the tutorial is about core JavaScript, the language itself. Later on, you'll learn about Node.js and other platforms that use it.
+This part of the tutorial is about core JavaScript, the language itself.
 
 But we need a working environment to run our scripts and, since this book is online, the browser is a good choice. We'll keep the amount of browser-specific commands (like `alert`) to a minimum so that you don't spend time on them if you plan to concentrate on another environment (like Node.js). We'll focus on JavaScript in the browser in the [next part](/ui) of the tutorial.
 
@@ -46,7 +46,7 @@ The `<script>` tag contains JavaScript code which is automatically executed when
 The `<script>` tag has a few attributes that are rarely used nowadays but can still be found in old code:
 
 The `type` attribute: <code>&lt;script <u>type</u>=...&gt;</code>
-: The old HTML standard, HTML4, required a script to have a `type`. Usually it was `type="text/javascript"`. It's not required anymore. Also, the modern HTML standard, HTML5, totally changed the meaning of this attribute. Now, it can be used for JavaScript modules. But that's an advanced topic; we'll talk about modules in another part of the tutorial.
+: The old HTML standard, HTML4, required a script to have a `type`. Usually it was `type="text/javascript"`. It's not required anymore. Also, the modern HTML standard totally changed the meaning of this attribute. Now, it can be used for JavaScript modules. But that's an advanced topic; we'll talk about modules in another part of the tutorial.
 
 The `language` attribute: <code>&lt;script <u>language</u>=...&gt;</code>
 : This attribute was meant to show the language of the script. This attribute no longer makes sense because JavaScript is the default language. There is no need to use it.
@@ -73,9 +73,7 @@ Script files are attached to HTML with the `src` attribute:
 <script src="/path/to/script.js"></script>
 ```
 
-Here, `/path/to/script.js` is an absolute path to the script file (from the site root).
-
-You can also provide a relative path from the current page. For instance, `src="script.js"` would mean a file `"script.js"` in the current folder.
+Here, `/path/to/script.js` is an absolute path to the script from the site root. One can also provide a relative path from the current page. For instance, `src="script.js"` would mean a file `"script.js"` in the current folder.
 
 We can give a full URL as well. For instance:
 

1-js/01-getting-started/1-intro/limitations@2x.png

@@ -4,7 +4,7 @@ For a long time, JavaScript evolved without compatibility issues. New features w
 
 That had the benefit of never breaking existing code. But the downside was that any mistake or an imperfect decision made by JavaScript's creators got stuck in the language forever.
 
-This was the case until 2009 when ECMAScript 5 (ES5) appeared. It added new features to the language and modified some of the existing ones. To keep the old code working, most modifications are off by default. You need to explicitly enable them with a special directive: `"use strict"`.
+This was the case until 2009 when ECMAScript 5 (ES5) appeared. It added new features to the language and modified some of the existing ones. To keep the old code working, most such modifications are off by default. You need to explicitly enable them with a special directive: `"use strict"`.
 
 ## "use strict"
 
@@ -19,9 +19,7 @@ For example:
 ...
 ```
 
-We will learn functions (a way to group commands) soon.
-
-Looking ahead, let's just note that `"use strict"` can be put at the start of most kinds of functions instead of the whole script. Doing that enables strict mode in that function only. But usually, people use it for the whole script.
+We will learn functions (a way to group commands) soon. Looking ahead, let's note that `"use strict"` can be put at the start of most kinds of functions instead of the whole script. Doing that enables strict mode in that function only. But usually, people use it for the whole script.
 
 
 ````warn header="Ensure that \"use strict\" is at the top"

1-js/01-getting-started/4-devtools/article.md

@@ -1,4 +1,4 @@
-First, the variable for the name of our planet.
+## The variable for our planet
 
 That's simple:
 
@@ -8,7 +8,7 @@ let ourPlanetName = "Earth";
 
 Note, we could use a shorter name `planet`, but it might be not obvious what planet it refers to. It's nice to be more verbose. At least until the variable isNotTooLong.
 
-Second, the name of the current visitor:
+## The name of the current visitor
 
 ```js
 let currentUserName = "John";