javascript - Compute differences between 2 HTML pages and dynamically change first -

I have a Html page that generates (again) every 3 seconds and exposes users to these changes is required. / P>

Since I can not change the generator to write a different format (JSN) and read using AJAX, we just have a javascript that refreshes the whole page every 10 seconds.

Ideally, instead of refreshing the whole page, what I want to do is just refresh those areas that have changed

The structure of the page never changes, only the value of table cells . Each table cell has a different class name.

Ex:

The basic HTML running in the user's browser includes:

  & lt; Html & gt; & Lt; Body & gt; & Lt; Div class = "first die" & gt; 1000 & lt; / Div & gt; & Lt; / Body & gt; & Lt; / Html & gt;  

After 3 seconds it changes to the server:

  & lt; Html & gt; & Lt; Body & gt; & Lt; Div class = "firstdiv" & gt; 2000 & lt; / Div & gt; & Lt; / Body & gt; & Lt; / Html & gt;  

A javascript will be read through AJAX every 3 seconds changed HTML, calculate the difference and only the user whose browser has already been opened in the browser, using Javascript:

  $ ('firstdiv.') HTML ('2000).  

So my question is: Is there a device / library that can help me with this task?