Disadvantages of Ajax

1. Integration of the browsers. Back button may not work, one can use invisible iframes to fix this problem like Google Maps.
2. Hard to bookmark page, can use URL fragment identifier.
3. Latency within networks
4. Some search engines are not equipped for Ajax. Google cannot index it
5. Accessiblity: a site may have to provide a non-Ajax version for users of non-compliant browsers.
6. Security: cross-site scripting. There are few resources for developers to create secure Ajax code.