JavaScript Variables and Operators

JavaScript Variables

As in other programming languages JavaScript also uses equal to = operator to assign the value to the left side variable.

Example

x = 10;

It will assign value 10 to the variable x.

In JavaScript you can use var keyword to declare the variable.

Example

var x;
var y;

x = 10;
y = x;

Above example shows 2 variables x and y.

x is assigned value 10. Then y is assigned value equal to x.

JavaScript is a case sensitive language so variable names are also case sensitive. If you are declaring variables as var x, var X then both variables are totally different.

JavaScript + OperatorOperator in JavaScript is used for 2 purposes, one for arithmetic operation of addition and second for string concatenation.

JavaScript + Operator Addition Example

var x;
var y;
var z;

x = 10;
y = 20;
z = x + y;

Above JavaScript, after execution will set the value of z = 30.

If you will use quotes to set the values for variables, then + operator will work as string concatenation.

Example

var x;
var y;
var z;

x = "10";
y = "20";
z = x + y;

This JavaScript code will generate the result z = 1020.

Another example of string concatenation in JavaScript:

var str1 = "Learn Programming ";
var str2 = "in JavaScript";
var msg = str1 + str2;

It will concatenate the 2 strings to generate the output as Learn Programming in JavaScript.

If you want to concatenate any other string without variable, then can you do it like this:

var msg = str1 + str2 + " with QuickStart Tutorials."