Javascript how to add leading zero at the front of month and day

Hi there.
How to add leading zero at the front of month and day field. For example,
From 2018/6/6  to 2018/06/06  YYYYMMDD

Normally we would use datetimepicker.js for the job. What if it did not show the leading zero at front of the month or day. We can add revise it by using -slide(-2) function and by if condition

Method 1: Slice(-2) function

if (this.Format.toUpperCase()=="YYYYMMDD") return (this.Year)+DateSeparator+("0"+(this.Month+1)).slice(-2)+DateSeparator+("0"+pDate).slice(-2);

Method 2: If condition

if (this.Format.toUpperCase()=="YYYYMMDD") return (this.Year)+DateSeparator+((this.Month+1)<=9?'0'+(this.Month+1):(this.Month+1))+DateSeparator+((pDate)<10?'0'+(pDate):(pDate) );

Hope it helps and happy coding.