Ajaxium

Ajaxium replaces ASP.NET postbacks by AJAX, transforming existing ASP.NET applications to Web 2.0 without JavaScript callbacks or server-side coding. In contrast to other AJAX-based approaches, Ajaxium-powered sites remain accessible to search engines and old browsers due to an automatic and silent degradation to classic ASP.NET. What's more, Ajaxium supports custom and third-party ASP.NET controls in addition to all default ASP.NET controls.