Developer tools are essential in increasing the productivity of the developers. The more the developer knows about using various tools, the quicker he gets his work done.

When working with console applications or windows applications; IDE's like Visual Studio, Eclipse, Netbeans etc. provide extensive features to code, refactor, run, debug, test, troubleshoot them. When it comes to Web applications the extend of features provided is limited. Especially when it comes to debugging, troubleshooting the web applications.

There could have been many reasons as to why such a support was not provided initially, some of them are

Web Application Container or Application server

The web application is deployed into an application server that manages the life cycle of the web application. Since that is a separate application, the IDEs need to interact with that application when debugging the deployed application. So there needs to be a communication protocol defined between the IDEs and the application servers. The application server vendors need to incorporate that functionality into their products or they publish a plugin API using which the IDE vendors themselves build that functionality. Either way this is a separate undertaking on it own, which needs to be maintained across IDE versions/programming language versions/application server versions.

Web Browser

A typical web application interaction involves the web browser, application server and the deployed application. The web application pages needs to look fine on various browsers and their variants. To debug client side scripts in the web aplication, the IDEs need to interact with the browsers. Which again brings back the same vendor support APIs or plugin APIs and their maintenance.

Microsoft which has one of the best developer friendly applications, initially released the Script Debugger which can be used to debug client side script of web applications separately. Since IIS was their product it must have been easy for them to build the server-side debugging of ASP and ASP.NET. We also had Venkman JavaScript for firefox. With the popularity of firefox addons a lot more tools were created. A few of such tools are explained in this article.