单击缩略图而不加载ajax即可加载文章

Question

As shown in the demo(link below), when an article thumbnail was clicked, the full article appeared and the page did not refresh nor ajax was used.

Demo link:
http://tympanus.net/Development/AnimatedGridLayout/

Questions:

1. By looking at the source code, the full article was actually loaded but hidden and was shown after I clicked on the thumbnail. How did she manage to assign this X thumbnail to X article? I couldn't find any references that link them up.
2. I want to achieve such effect too, is there any easier way to do it?

Download source code link:
http://tympanus.net/codrops/2015/04/15/grid-item-animation-layout/

Answer 1

If i undesrtand correctly, for assigning X thumbnail to X article uses the position of the item in the array.

Easier would be using id for each thumbnail and directly reference the article.