Question

I am using a for-in loop to iterate over an array of two elements, but it is like its looping twice.

I have an example here: http://jsbin.com/etoyac/8/

Answer 1

It’s because the result returned from getElementsByTagName isn’t a simple array — it’s a NodeList and it’s “live”. Updates you make to the DOM are reflected in the list immediately.

You can use the “slice” method on the Array prototype to turn the NodeList into an array:

var slideArr = [].slice.call(slides, 0);

Also you should iterate through the array (or the NodeList for that matter) with a numeric index:

for (var slideIndex = 0; slideIndex < slideArr.length; ++slideIndex) {