The remainder operator in JavaScript is used to get the remaining value when an operand is divided by another operand. In some languages, % is considered modulo. Modulo and Remainder work differently when the sign of both operands is different.
In JavaScript remainder takes the sign of the dividend and to get modulo ((a % n) + n) % n should be used instead of a % n.
Syntax
remainder = var1 % var2
Example 1: This example returns the positive remainder in this case both modulo and remainder will be the same as both operands are positive.
Javascript
<script>    // Initializing variables    var a =4    var n = 2         // Calculating remainder    var rem = a%n         // Calculating modulo    var mod = ((a%n)+n)%n         // Printing result    console.log("Remainder is "+rem)    console.log("Modulo is "+mod)</script> |
Output:
"Remainder is 0" "Modulo is 0"
Example 2: This example returns a negative remainder as the dividend is negative.
Javascript
<script>    // Initializing variables    var a =-4    var n = 2         // Calculating remainder    var rem = a%n         // Calculating modulo    var mod = ((a%n)+n)%n         // Printing result    console.log(rem)    console.log(mod)</script> |
Output:
-0 0
Example 3: Remainder with Infinity and NaN
Javascript
<script>    // Both operands are NaN    console.log(NaN%NaN)         // Dividend is NaN    console.log(NaN%2)         // Dividend is Nan and Divisor is Infinity    console.log(NaN%Infinity)         // Dividend is Infinity and Divisor is NaN    console.log(Infinity%NaN)         // Both operands are Infinity    console.log(Infinity%Infinity)         // Dividend is infinity    console.log(Infinity%5)</script> |
Output:
NaN NaN NaN NaN NaN NaN
We have a complete list of Javascript Operators, to check those please go through the Javascript Operators Complete Reference article.
