Do search engines process Javascript?

Question

According to this page it would seem like they don't, in the sense that they don't actually run it, but that page is 2 years old (judging from the copyright info).

The reason I'm asking this question is because we use Javascript to replace text on our site with other more typographically sound content. We're worried that this may affect the crawlability/seo of our sites, since generally what we're replacing is headers; ie. <h1>, <h2>, etc.

Will search engine bots see our original code, or will they run the Javascript and see the replaced text?

Answer 1

Generally no. Google has mentioned that they are working on a system of indexing ajax content, but I don't think any of the major search engines index dynamic content as a rule. See this page for Google's take on it: http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=81766

Answer 2

I'd use metadata to ensure bots pick up the content on your pages.

Answer 3

Search engines don't process JavaScript as such.

There is some evidence that Google may have started processing inline script content in some cases, in order to catch content that is entered into the page parse queue using document.write. However certainly DOM methods such as you might use for font-replacement are not affected and no onload code is invoked.

Answer 4

The bots will certainly not run the Javascript code, but they might recognise some commonly used scripts.

You shouldn't count on it though. Clear markup, proper content and real links is still what counts.

Also, if the bots happen to recognise your script, it might not be in your favor. If the code is recognised as something that is commonly used to try to fool bots, it could even hurt your page ranking.