Remainder (%)
  The remainder operator (%) returns the remainder left over when one
  operand is divided by a second operand. It always takes the sign of the dividend.
  Note that while in most languages, '%' is a remainder operator, in some
  (e.g. Python, Perl)
  it is a modulo operator.
  For two values of the same sign, the two are equivalent, but
  when the dividend and divisor are of different signs, they give different results. To
  obtain a modulo in JavaScript, in place of a % n, use
  ((a % n ) + n ) % n.
Syntax
x % y
Examples
Remainder with positive dividend
 13 % 5  //  3
 1 % -2 //  1
 1 % 2  //  1
 2 % 3  //  2
5.5 % 2 // 1.5
Remainder with negative dividend
-13 % 5 // -3
-1 % 2  // -1
-4 % 2  // -0
Remainder with NaN
NaN % 2 // NaN
Remainder with Infinity
Infinity % 2 // NaN
Infinity % 0 // NaN
Infinity % Infinity // NaN
Specifications
| Specification | 
|---|
| ECMAScript Language Specification # sec-multiplicative-operators | 
Browser compatibility
BCD tables only load in the browser