Last year Google posted on their Webmaster Central Blog that they would begin executing and crawling Javascript on websites to better understand dynamic web content: http://googlewebmastercentral.blogspot.com/2014/05/understanding-web-pages-better.html
Merkle | RKG ran a series of tests to determine just how well the Googlebot was able to crawl and index Javascript, and Search Engine Land recently posted the results.
Think Google can’t handle JavaScript? Think again. Contributor Adam Audette shares the results of a series of tests conducted by his colleagues at Merkle | RKG to examine how different JavaScript functions would be crawled and indexed by Google.
Source: We Tested How Googlebot Crawls Javascript And Here’s What We Learned