Google does not interpret Javascript javascript so the Googlebot does not index and therefore not read what is inside the pop up windows opened with javascript. Another mistake that can be found by using javascript is when you develop a menu with javascript redirect links. These links are not followed by Googlebot, so the pages which point the javascript links will not be followed. Flash Other topics that have filled post and more post in the forums is the use or non-use of Macromedia Flash. I have to admit that I personally love technology as flash with it can develop very showy Websites who manage to stunning visual effects which are impossible to do with pure html. Well, for fans of this technology I have very bad news as the subject of search engine optimization is very harmful.
Google can not read the content contained within Flash movies. Discouraging the use of this technology for full web development, I recommend using mixed with extracting html content outside the flash movie. You can see an example with my site, find the perfect blend of flash and html. Be essential to develop a website entirely in flash recommend a flash to make 2 versions and other html, blocking the spiders to the flash version via the robots.txt file with dynamic content sites often want to have a website containing a large amount of content and that this be renewed often. With current technologies, the most logical and convenient to use a server side technology combined with a kiss of data.
Search engines have many shortcomings to explore these pages and got almost none to solve this problem. Google is one of the best reading dynamic sites but very rarely can read urls that contain more than two variables. There are ways to eliminate the variables in the urls to make them search engine friendly: for example, servers with php apache module mod_rewrite can use a search engine to treat the dynamic and static url.