Closures and Recursion in JavaScript

closure_recursion_1.js

var SlideChanger = function(seconds_each) {
  var index = -1; 
  // on the first cycle, index will be set to zero below
  var maxindex = ($(".change_link").length) - 1; 
  // how many total slides are there (count the slide buttons)
  var timer = function() { 
  // this is the function returned by SlideChanger
    var logic = function() { 
    // this is an inner function which uses the 
    // enclosed values (index and maxindex) to cycle through the slides
      if (index == maxindex) 
        index = 0; // reset to first slide
      else
        index++; // goto next slide, set index to zero on first cycle
      $('.slideshow').blinds_change(index); // this is what changes the slide
      setTimeout(logic, 1000 * seconds_each); 
      // schedule ourself to run in the future
    }
    logic(); // get the ball rolling
  }
  return timer; // give caller the function
}

SlideChanger(5)(); // get the function at five seconds per slide and run it

closure_recursion_2.js

(function(seconds_each) {
  var index = -1; 
  // on the first cycle, index will be set to zero below
  var maxindex = ($(".change_link").length) - 1; 
  // how many total slides are there (count the slide buttons)
  return function() { 
  // this is the function returned by SlideChanger
    var logic = function() { 
    // this is an inner function which uses the 
    // enclosed values (index and maxindex) to cycle through the slides
      if (index == maxindex) 
        index = 0; // reset to first slide
      else
        index++; // goto next slide, set index to zero on first cycle
      $('.slideshow').blinds_change(index); // this is what changes the slide
      setTimeout(logic, 1000 * seconds_each); 
      // schedule ourself to run in the future
    }
    logic(); // get the ball rolling
  }
})(5)(); // get the function at five seconds per slide and run it