I am trying to understand the whole Ajax functionality in a website and how jQuery handles

the calls.  

I have a page that needs to update values every 3 seconds as an example say a clock. Using

Ajax will only update that field, but there's no loading of the rest of the DOM, icons, images, etc..

 

Currently, I am using the following:

           .....

          ...

          .

          say the clock field is in here

          ......

          ...

        },3000);

});

I am finding that this is producing a lot traffic, while inspecting it with WireShark software.

Can this be done in a better way (that produces less traffic)?