how to get the last two digits of a date in javascript code example

Example: get last two digits of year javascript

maskDate(date) {
    // console.log(date);
    var dateVar = new Date(date);
    // console.log("XX/XX/"+ dateVar.getFullYear().toString().substr(-2));
    return "XX/XX/"+ dateVar.getFullYear().toString().substr(-2);
 }