How to use Add Operator in Javascript

Description

The add operator + is used in the following example:

The add operator behaves differently for special values, as follows:

• If the two operands are numbers, perform an add.
• If either operand is NaN, the result is NaN.
• For Infinity + Infinity, the result is Infinity.
• For -Infinity + -Infinity, the result is -Infinity.
• If Infinity + -Infinity, the result is NaN.
• If +0 adds +0, the result is +0.
• If -0 adds to +0, the result is +0.
• If -0 adds -0, the result is -0.
• If both operands are strings, the second string is concatenated to the first.
• If only one operand is a string, the other operand is converted to a string then concatenate.
• If either operand is an object, number, or Boolean, its toString() method is called to get a string value and then concatenate two strings.
• For undefined and null, the String() function is called to retrieve the values "undefined" and "null", respectively.

Example

var result1 = 1 + 5;     
console.log(result1);    //from  w  w  w  .  j  a  v a  2  s.c o m
var result2 = 1 + "5";   
console.log(result2);    

var num1 = 1;
var num2 = 2;
var message = "The sum is " + num1 + num2;
console.log(message);    
var message = "The sum is " + (num1 + num2);
console.log(message);

The code above generates the following result.