Ajax has only advantages? As with all things of this world it is too peremptory statement, then some (of course debatable) disadvantages to this technology:
- Too much code: Introduce Web application pages in many cases the Internet is “drowning” of code, too much code will take more performances by the browser that will work more slowly;
- Uncertainty: Using Ajax is used often using ready-made solutions created by others, think of the countless plugins for the various frameworks, who assures that these are safe?
- Compatibility is a bit of CSS and the same speech again is not the fault of technology, the browsers do not offer it the same level of support, a factor that often requires developers to deal with working time longer.
- Search Engines: one of the reasons for success of Ajax, it regards the fact that in many cases it eliminates the need of having to reload pages to access a resource, but crowded pages of content including tabbed window, and hidden div bubble tooltips can make pages search engine friendly?
- Sailing times: each time a web applications means waiting a response from the Web server, so good for those with broadband (very) large
It very likely that over time some of the disadvantages listed will eventually disappear or become less important.