//Select all elements on the page with the name attribute equal to VCRImage

var images = document.querySelectorAll('[name=VCRImage]');

​

//For each image bind the click event

for(var i=0; i < images.length; i++)

{

  var image = images[i];

  //https://developer.mozilla.org/en-US/docs/Web/API/EventTarget.addEventListener

  image.addEventListener('click', imageClicked.call(image), false);

}

​

function imageClicked()

{

  //get images in the set

  var imageSet = this.getAttribute('data-altsrc').split(',');

  //Use a closure to wrap the counter variable

  //so each image element has their own unique counter

  var counter = 0;

  return function(event)

  {

    //Increment counter

    counter++;

    //The context of "this" is the image element

    //Use a modulus

    this.src = imageSet[counter % imageSet.length];

  }

}

​