Based on user's selection of a choice from the select control on a aspx page, I want to add different sets of fields (basically append to the bottom) to the same page. Let us say, user selects Choice1, I add two text fields, when user selects choice2 then I add a select and a text field. How can I accomplish this. Can someone give me an example?

Put the fields on the page and use the "Visible" property to turn the appropriate ones on and off based on the choices made. You can also group together HTML in an asp:panel so you turn "sections" on and off.