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# Part 2 - Javascript For Beginners

Shiva Bhusal
·Jan 6, 2021·

### Introduction

This webpage is a continuation of a beginner's guide to JavaScript and covers topics such as data types, conditional statements, loops, and functions.

### What are Basic operators?

Basic operators are addition `+`, multiplication `*`, subtraction `-`, Division `/`, Remainder `%` , Exponentiation `**`.and so on. For example:

``````
alert( 5 % 2 ); // 1, a remainder of 5 divided by 2 //Remainder operator

alert( 2 ** 2 ); // 4  (2 multiplied by itself 2 times) //Exponentiation operator
``````

### What is String concatenation? String concatenation means merging/connecting two strings with the plus operator '+'.

For Example:

``````
let str = "my" + "string";//alert(str); // mystring

alert( '1' + 2 ); // "12"
alert( 2 + '1' ); // "21"

alert(2 + 2 + '1' ); // "41" here firstly two numbers are added then 4 is converted to string then, adds string '4' to string '1'.
``````

From this above example, we can understand that string '1' tries to convert number 2 to string and adds 12 whereas "21" is also the same 2 is converted at the string and added with string '1' and so on.

Rules of '+=' and '*=' operators:

``````
let n = 2;
n += 5; // n = 7 operator + is calculated first like 2+5=7.
n *= 2; // n = 14 now value of 'n' is 7 so 7*2=14.

``````

### How are Increment/decrement operations done?

Increment++ increases a variable by '1'. Decrement-- decreases a variable by '1'.

For Example:

``````
let counter = 2;
counter++;        // 2+1=3 increment by '1'.
alert( counter ); // returns 3

let counter = 2;
counter--;        //2-1=1 decrement by '1'.

let a = 1, b = 1;
alert( ++a ); // 2, prefix form returns the new value
alert( b++ ); // 1, postfix form returns the old value

alert( a ); // 2, incremented once
alert( b ); // 2, incremented once
``````

### What are comparison operators?

Comparison operators are those operators which are used for comparing two operands.

``````
1. a > b, a < b // greater than less then operators.
2. a >= b, a <= b // greater/less then equal to.
3. a == b // eqality test.
4. a = b // assigning value 'a' to value 'b'.
5. a != b // 'a' is not equal to 'b'.
6. a === b //strict operator

Simple Example:
alert( 2 > 1 );  // true
alert( 2 == 1 ); // false
alert( 2 != 1 ); // true
``````

### What is Conditional branching?

conditional branching is the term used to describe operations such as 'if(condition)', 'else(condition)', 'else if', and 'if else' by using different operators.

For Example:

``````
let year = prompt('In which year was the ECMAScript-2015 specification published?', '');

if (year < 2015) {
} else if (year > 2015) {
} else {
Note: A number 0, an empty string ``""` `, null, undefined, and NaN all become false. Because of that, they are called “falsy” values. Other values become true, so they are called “truthy”.