Add content for scope in JavaScript (#2769)

content/roadmaps/106-javascript/content/101-javascript-variables/103-scopes/readme.md

@@ -1,6 +1,15 @@
 # Scopes
 
-Before ES6 (2015), JavaScript had only Global Scope and Function Scope. ES6 introduced two important new JavaScript keywords: `let` and `const`. These two keywords provide Block Scope in JavaScript.
+In JavaScript, scope refers to the visibility of a variable or how it can be used after it is declared. The scope of a variable depends on the keyword that was used to declare it.
+
+The three types of Scope are Global Scope, Function Scope, and Block Scope. Before ES6 (2015), JavaScript had only Global Scope and Function Scope with the `var` keyword. ES6 introduced `let` and `const` which allow Block Scope in JavaScript.
+
+Global Scope: Variables declared outside any function or curly braces '{}' have Global Scope, and can be accessed from anywhere within the same Javascript code. `var`, `let` and `const` all provide this Scope.
+
+Function Scope: Variables declared within a function can only be used within that same function. Outside that function, they are undefined. `var`, `let` and `const` all provide this Scope.
+
+Block Scope: A block is any part of JavaScript code bounded by '{}'. Variables declared within a block can not be accessed outside that block. This Scope is only provided by the `let` and `const` keywords. If you declare a variable within a block using the `var` keyword, it will NOT have Block Scope.
+
 
 <ResourceGroupTitle>Free Content</ResourceGroupTitle>
 <BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.w3schools.com/js/js_scope.asp'>JavaScript Scope</BadgeLink>