Ajax is a new way of using two existing technologies, to make websites faster, and more user friendly.
To explain this, we have written an example below. Normally, when you change something on a web page, the browser needs to go back to the server to get an updated copy of that page. However, if you choose sizes for the items below, only that part of the page changes. There are two important things happening here. First, as there is less data going to and from the server, all of this happens very quickly for the website user. Second, as this is quite low on the page, the page is not returned to the top (meaning you would have to scroll down again,) which can be very annoying.
Select the series "Clamp" below. Now select "B14" as the "d1". You can see that the options for "D2" have been reduced to one. Now select any item for "Finish". You will see that you have been given a complete part code. This is because the remaining two parameters for which you haven't selected a value both only have one possibility, therefore there is only one possible part code that can be displayed. Selecting greyed-out values will override any previous parameter you have selected.