Infinite scroll and returning to front page position

We need to implement a functionality wherein on clicking the back button, the site visitor comes back to the same position he or she clicked out of on the front page.

Currently the theme we are using takes the viewer all the way back up to the top of the page, forcing him or her to scroll all the way back down to where she was when she clicked on product detail.

A good example of what we need is here: http://www.jabong.com/men/clothing/mens-t-shirts/

I realize this isn’t a WP site, but I wanted to give a simple example: where you scroll down and hit on a product, and click back from the product page, you reach the same position of the page where that product is.

The example shown here doesn’t seem to append anything in the url to remember the position.

The theme we are using now is infinite scrolling pagination (like pinterest), and the pages keep loading on scrolling down. When I go back, the query runs again and reloads the page. If I was on the 4th page before, after going back, the pages don’t load until page 4 and so there’s a break, thus I cant reach that position.

So my question is how do I do this with infinite scrolling?