date manipulation in javascript

Suppose I get a date via a jquery calendar to a java script variable. e.g: var d = 02/12/2011

How can I manipulate that date variable using a js function or jq method where to get the date 3 month ahead of that date? I cant just do following know. Because every month does not have 30 days?

var futureDate=n开发者_StackOverflow中文版ew Date(d);
futureDate.setDate(futureDate.getDate()+30*3);

You can try using either the Date.js or Sugar.js libraries. They both have great date manipulation functions.

Here's an example using Sugar...

var futureDate = Date.create(d);
futureDate.addMonths(3);

The value d can be anything that Sugar understands as a date which is quite flexible.

Use futureDate.setMonth(futureDate.getMonth() + 3)

This will work towards the end of the year too. It roll over to the new year automatically.

Here's a good routine that can handle that and lots of other date manipulations:

http://slingfive.com/pages/code/jsDate/jsDate.html