Web applications implement business logic. Business logic is a rule or process that affects the business state of the system.
The Document Object Model (DOM) is a platform-neutral interface to the browser and the HTML or XML documents it's rendering.
The browser is responsible for executing client-side scripts.
Dynamic HTML (DHTML) is a vendor term that describes a combination of HTML, style sheets, and scripts that allow documents to be manipulated in a Web browser. It is not a W3C specification or recommendation.