http://news.cnet.com/8301-1023_3-10220532-93.html

"...
Specifically, Google is trying out a new way to present search results that uses the JavaScript programming language and the related Ajax interface technology, not just regular HTML, to display the information, Google spokesman Eitan Bencuya said.

The reason: with the Ajax-enhanced search results, JavaScript is used to load the actual search results beneath the unchanging boilerplate above, a tactic that means only the search results need to be loaded on subsequent searches.
..."