02-1-common-syntax.md

2.1 Basic Syntax

Javascript is interpreted line by line. Each line written is read and the interpreter 'executes' the line before moving on to read the next line. The meaning of a line to the Javascript interpreter is not the same as what a line means to a text editor. A "line of code" could be more or less than a "line of text". Lines can be optionally terminated with ;(semicolon) in Javascript.

The following, although written in one line, is technically two lines for the interpreter.

var a = 10; window.alert(a);

Similarly the following declaration of function, although takes 3 lines, will be just a single line when the interpreter goes through it for the first time

function myFun () {
    window.alert('hello')
}

2.1.1 Comments

Comments are lines in your code that are ignored by the interpreter. Lines that start with // are considered as single line comment.

var a = 10;
// This is a comment
var str = 'this is not a comment';

There are also multi-line comments, started with /* and ended with */
Anything encountered between these two symbols are ignored by the interpreter.

var num = 10;
/* 
We begin a comment
And it continues
var k = 20
k wasn't actually declared, because we are in a comment
*/
var str = 'this is not a comment';