Question: Microsoft's [application](http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1=20120110437.PGNR.) aims to patent:

> 
> Methods and systems for style and/or layout caching of Web content are
> usable to build reusable style caching trees and cacheable layout
> calculations. Such style caching trees may be used to avoid
> recalculating style content of Web pages for document object model
> (DOM) elements that have not changed. Additionally, the cacheable
> layout calculations may be used to avoid recalculating the layout
> content of Web pages that are subsequently accessed.
> 
> 
> 

Claim 1 is:

> 
> A computer-implemented method comprising: performed by one or more processors executing computer-readable instructions:
> 
> 
> * receiving a Web page file;
> * parsing the Web page file to create a document object model (DOM) tree comprising DOM tree nodes;
> * constructing a style caching tree comprising structure information of the DOM tree;
> * storing the style caching tree in a memory;
> * constructing a render tree comprising render objects based at least in part on the structure information of the DOM tree;
> * performing a layout calculation for render objects;
> * and storing the layout calculation results in the memory.
> 
> 
> 

Can prior art be demonstrated from the WebKit and Gecko source trees from several years ago?

Answer: 
Claim 1 doesn't seem novel, everything seems to be described in an article from October 2009 (before the October 2010 filing date of this patent):

* "parsing the Web page file to create a document object model (DOM) tree comprising DOM tree nodes;" <http://taligarsiel.com/Projects/howbrowserswork1.htm#DOM>
* "constructing a style caching tree comprising structure information of the DOM tree;" <http://taligarsiel.com/Projects/howbrowserswork1.htm#Firefox_rule_tree>
* "storing the style caching tree in a memory;" *Where else you gonna put it?!?*
* "constructing a render tree comprising render objects based at least in part on the structure information of the DOM tree;" <http://taligarsiel.com/Projects/howbrowserswork1.htm#Render_tree_construction>
* "performing a layout calculation for render objects;" <http://taligarsiel.com/Projects/howbrowserswork1.htm#Layout>
* "and storing the layout calculation results in the memory." *Where else you gonna put it?!?*
One could argue there is prior art from the server-side "widget" cache of phpNuke

The term cache can be ambigous. The browser stores the page in memory (since Netscape 1.0 or earlier ), which is a form of cache.

Additionally, modifying DOM nodes without re-rendering the whole page has been done for a long time. Certainly before 2010 that Microsoft are suggesting in the patent.