In order to make ASP web applications run as fast as possible, round-trips to the server have to be minimized and therefore in traditional ASP, client-side (Javascript) events such as OnFocus/LostFocus, OnChange, OnKeyPress, OnBlur and OnClick were used as much as possible for formatting, calculating values, populating controls and more, to basically try to do as much on the client before going to the server. Whether is it a web application or a client-server application, as much should be done on the client before interacting with the server since servers are not necessary in the same building, city or even country anymore.<BR><BR>I am now building a Web application using the new .NET platform and using Web Form controls, which allows me to dynamically create server-side controls and then access the controls through code. This works really well after a trip is done to the server. I can populate the objects’ attributes from the Web Form controls and carry on with the business rule validations on the objects, and then populate the different tables.<BR><BR>As I was building my first Web Form application using the .NET platform, I realized the power of the Web Form controls, once the processing was back at the server. I was wondering if the client-side events and validation was going to be as powerful as the server-side processing. I started using the Validation Controls, which are easy to use and quite powerful. They allow both client-side and server-side validation, which is quite handy. Therefore validate as much as you can on the client (assuming you are running a proper browser - IE 5 and above) before a trip to the server and continue with the Business Rules validation. It works quite well aside of a few glitches but I am only running Beta2 and waiting for the production version.<BR><BR>So far not too bad I thought. I am now at the stage where I am getting a little fancier on the client-side, especially on the user interface where I will; validate controls, populate other controls, format values in controls, calculate values and populate controls all dynamically before even going to the server. I was hoping to find client-side events such as onFocus, LoseFocus, onKeyPress, OnBlur, and OnClick to allow me to manipulate values of Controls on the client to give a far more responsive interface like the traditional ASP client-side code allowed me to do. For example, if TextBox1’s value changes, I would like to populate TextBox2’s and calculate a total to populate TextBox3. <BR><BR>Since I did not find any of the previously traditional client-side events for the TextBox controls to allow me to calculate values or populate other TextBox controls depending on a value entered in another control, I was hoping to be able to use the CustomValidator control to allow me to do so. But since the ClientValidationFunction is a property and not and event, it can only be set to true or false and doesn’t allow me to interact with other controls while the client code is executed.<BR><BR>I have done quite a bit of research on it but have been unable to figure out this lack of client-side flexibility to provide users with a responsible interface without having generating round-trip to the server. I must have overlooked or misunderstood part of the Web Form controls or Validation Controls since I don’t quite believe that the client-side flexibility offered with the new .NET Server Controls and Validation Controls, would not be as good or even more powerful than the traditional client-side ASP to provide responsive user interfaces.<BR><BR>I would appreciate help on this matter whether it is; you are out-to-lunch on this issue and this is simply how we do it, or it is not available in the first release but could be available in the next release!<BR><BR>Thanks,<BR><BR>Max<BR>