Yesturday, Today, Tomorrow Dates To Call A Certain Image

I have a few functions I would like to develop using the date but I know very little about how best to start off coding for it in JavaScript.

I wanted to get three separate functions to handle getting yesterdays date, today's date, and tomorrows date. And was thinking about having the function call passed two paras being the id of the image and the var of the corresponding image path.

onclick="yesturdaysDate('sumImg',summary);"

var summary = "/path/to/directory/img"+dd+mm+yy+"type.jpg";
...or something like that?!

The format of the date (dd + mm + yy) is related to the file name of the image I want to call in.

I have had a look around on the web as I learn best from examples but found very little that wasn't well over the top or just plain too complex.

I found this that is close to the scale I was looking at the code to fill.

This gets today's date formatted in dd mm yy which is ideal.

var date = new Date();
var dd = date.getDate();
var day = (dd<10?&#390;'+dd:dd);
var mm = date.getMonth() + 1;
var month = (mm<10?&#390;'+mm:mm);
var yy = date.getYear();
var year = (yy<10?&#390;'+yy:yy);

Unfortunately it returns = 0308104 and I'm not really sure where the 1 has got in.