Remainder assignment (%=)

The remainder assignment operator (%=) divides a variable by the value of the right operand and assigns the remainder to the variable.

Operator: x %= y
Meaning:  x  = x % y

// Assuming the following variable
//  bar = 5

bar %= 2     // 1
bar %= 'foo' // NaN
bar %= 0     // NaN

• Assignment operators in the JS guide
• Remainder operator