var isbn = '0-7475-3469-9';

​

var x = 0;

var total = 0;

​

isbn = isbn.replace(/-/gi, '');

​

for (var i = 10; i !== 0; i--) {

    total += parseInt(isbn.charAt(x) * i);

    x++;

}

console.log(total);

​

 if(total % 11 === 0){

    console.log("yay!");

 } else {

    console.log('boo!');

 }