I don't understand what if " age % 2 !==0 " is instead " age % 2 !==1 "? [duplicate]

This question already has an answer here:

• What does % do in JavaScript? 8 answers
• understanding the modulus operator in javascript 3 answers

var age = prompt ("what is your age?");

if(age % 2 !== 0) {

alert ("Your age is odd!"); }