DHTML (dynamic HTML) is an umbrella term for client side programming technologies, including JavaScript, browser DOM (document object model), CSS (cascading style sheet), etc. Applications generated by Iron Speed Designer do not use the full functionality of the DHTML model for the following reasons:
Browser compatibility. DHTML relies heavily on client-side scripting and DHTML frequently introduces browser compatibility problems. The .NET component model used by Iron Speed Designer does not have these browser restrictions.
Complex dependencies. Every type of request made by a page needs to be supported by a web service or a helper page. This means that pages are not self-contained entities, and DHTML can lead to complicated run-time dependencies.
Component model programming is the preferred .NET architecture. Pages generated by Iron Speed Designer use a component model, where the components are given complete control over certain sections of the HTTP response. In order for an application to function properly, the page needs to get new data from the server, parse that data, and use it to modify the page. That requires that either: (a) the page itself has complete knowledge of the page's content in order to update it properly, or (b) the server-side component model be replicated on the client side. The former is not possible using a component model, and the latter would require extensive DHTML use (see #1).
Customization is difficult. One of the features of the Iron Speed component model is that it is customizable. You can override or extend the server-side functionality of the application pages and components. These customizations may include code that cannot be performed on the client side for technical, security, or other reasons.
Security risks. Placing application logic in client-side scripting frequently introduces security risks into your application.
One advantage to using DHTML is its ability to eliminate the page flashing caused when an application goes back to the server to fetch and display new data. Whenever a page needs to be updated using new data from the server, the current document is replaced using an HTTP Get (i.e. redirect) or HTTP Post (i.e. form submit) operation, which can cause page flashing.
Applications generated by Iron Speed Designer are designed to require as little DHTML support as possible, and to utilize limited DHTML in certain situations if the browser requesting the page supports it. However, the customizable aspect of Iron Speed Designer applications means that you can extend the application (or the application classes) to use existing technology. Depending on how your application works, you can avoid some, or even all, page flashing. Using JavaScript, IFrames or Layers, etc., it is possible to download web content from a server, and use that content to dynamically modify or update the current page's content, without page flashing.