1. A computer-implemented method for constructing client-server applications comprised of first, second, and third tier programming logic for a three tier computer network architecture using a computer-implemented Rapid Application Development (RAD) tool, the method comprising: displaying the first tier programming logic in a first window module, the first tier programming logic comprising a web browser capable of containing and executing applets, wherein the first tier programming logic communicates with the second and third tier programming logic; displaying the second tier programming logic in a second window module, the second tier programming logic comprising one or more second tier application scripts executed by a second tier runtime module that interfaces to a web server, wherein the second tier programming logic communicates with the first and third tier programming logic; displaying the third tier programming logic in a third window module, the third tier programming logic comprising one or more third tier application scripts executed by a third tier runtime module that interfaces to a database management system, wherein the database management system receives requests from the second tier programming logic and the third tier runtime module, performs database functions in response to the requests, and returns results from the performed database functions; so that as a user interacts with the first tier programming logic in the first window module, the second and third tier programming logic are executed in response thereto, breakpoints are selectively triggered within the executed second and third tier programming logic, and the selectively triggered breakpoints are displayed in the second and third window modules, respectively; wherein the first tier programming logic further comprises "Run Local/Run Remote" functions for executing the second and third tier programming logic, wherein the "RunLocal" function is selected to execute the second and third tier programming logic on a development computer and the "RunRemote" function is selected to execute the second and third tier programming logic on different computers.