Historically, Google indexing system was constructed by analogy with a text browser such as Lynx, so it was important for only the availability and accessibility of the text on the page. But now the system works similarly to other browsers, so you need to pay attention to the following points:
- Like all modern browsers, search robot may not support some of the technology used on the pages. It is necessary to ensure that the design of the site follows the principles of progressive enhancement, this will help google to see useful content and basic functionality, when some of the design features are not yet supported.
- Verify that the server normally accept an additional load of stored scripts and styles by Googlebot.
In the panel for webmasters (tool "View as Googlebot"), you can see how the search engine handles certain page, where you can find some of the features of indexing, for example, closed in robots.txt files, redirects (which Googlebot does not go), and other.