I actually wanted to have something, where a user can choose a date from jquery datepicker and set the target date for countdown timer. 

I already have edited the code ( http://pastebin.com/NHRuJ5mL) and the output you can see ( http://goo.gl/OECkt). 

Actually put all of your code inside datepicker onSelect option. So when i select a date a timestamp is created and countdown timer is initiallized. But the problem is when ever i change the date plugin function is called once again and new instance is created with previous one. That mean it shows two countdown timer in my html page. If i do change the date it shows three countdown timer.

So i need a system where i will change the date and previous instance will be destroyed and new instance will work. The script is actually calling the plugin function by passing parameter. If i can dynamically pass the parameter hope it will solve the problem.