var now = new Date();
now = new Date(now.getTime() - 86400000);
var year= now.getFullYear(), month= (now.getMonth() + 1).toString(), day = now .getDate().toString();
if (month.length == 1) {
month= '0' + month;
}
if (day .length == 1) {
day = '0' + day ;
}
var dates=(year+ '-' + month+ '-' + day );
now = new Date(now.getTime() - 86400000);
var year= now.getFullYear(), month= (now.getMonth() + 1).toString(), day = now .getDate().toString();
if (month.length == 1) {
month= '0' + month;
}
if (day .length == 1) {
day = '0' + day ;
}
var dates=(year+ '-' + month+ '-' + day );
console.log(dates);//前一天