I'm an intermediate jQuery user and I want to build my very first (and hopefully useful) plug in. My question is really simple. When should I use a public and when a private function into the plug in code? They both work well, so why we need them both?

1. ;(function($) {
2.  //plugin code... 
3. // Private function
4. function privateFunc() { };
5. // Public function
6. $.fn.plugin.publicFunc = function(){ };
7.  })(jQuery);