How the page load is done

How the page load is done

Hi,
I am testing a template called devoops and when I navigate from page to another that a progress bar appear and start to load inside the page itself then disappear and the page appear without the page itself reload like normal using of href tag. The URL become like this

http://localhost/devoops/index.php#ajax/charts_xcharts.html

And if I create new page in the ajax folder and calle it using href I find the page also load the same way.

I want to know only how to load a page like this, what scripts I should use ?.

Here is the template

http://devoops.me/themes/devoops2/devoops2.zip