It featured a new Split View editor for simultaneous HTML and design viewing, built-in support for ASP.NET AJAX , and significantly better IntelliSense for JavaScript.
The environment also saw significant improvements in web development through ASP.NET AJAX. As the internet moved toward more interactive, "app-like" experiences, Visual Studio 2008 provided the tools necessary to build responsive web pages with less overhead. It also introduced better JavaScript support, including IntelliSense and debugging features that were previously rudimentary. These additions acknowledged the growing importance of client-side scripting and the burgeoning demand for high-performance web applications. microsoft visual studio 2008