Code For Setting the date as date before three days

We need to convert the current date to US time zone and need to find the date before three days ago from this.We can use the below code to achieve this.

//obtain the current date
 var  date =new Date();
//converting current date to US time zone
                var usTime = format.format({
                    value : date,
                    type : format.Type.DATETIME,
                    timezone : format.Timezone.AMERICA_NEW_YORK
                }); 
//setting the date as date before three days
               var us_date=new Date(usTime.split(' ')[0]);
                us_date.setDate(us_date.getDate() - 3);
                var threedaysago = (us_date.getMonth()+1)+'/'+ us_date.getDate()              +'/'+us_date.getFullYear();