JavaScript Addition Assignment Operator

Addition Assignment

In JavaScript, Addition assignment operator takes two operands, adds the value in right operand to that of the left operand, and assigns the result back to the left operand.


+= symbol is used for addition assignment operator.

a += 5  //equivalent to a = a + 5
a += b  //equivalent to a = a + b


1. Addition assign a with 5.

var a = 4;
a += 5;

2. Add a with value in b and assign the result back to a.

var b = 7;
var a = 4;
a += b;