get last two digits of year javascript

var strDate = new Date(); // By default Date empty constructor give you Date.now
var shortYear = strDate.getFullYear(); 
// Add this line
var twoDigitYear = shortYear.toString().substr(-2);const id = "ctl03_Tabs1";
console.log(id.slice(id.length - 5)); //Outputs: Tabs1
console.log(id.slice(id.length - 1)); //Outputs: 1 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);
 }