以xx-xx-xx的格式输出今天的日期

var  today = new Date();
function dateNow(dt) {
    if(!dt){
        dt = new Date();
    }
    var year = today.getFullYear();
    var month = today.getMonth() + 1;
    var date = today.getDate();
    if (month < 10){
        month = '0' + month;
    }
    if(date < 10){
        date = '0' + date;
    }
    return year + '-' + month + '-' + date
}

var getToday = dateNow(today);
console.log(getToday);