在页面加载时在asp.net上呈现数据的最佳方法是什么

our project is developed with dot net 3.5 and we use update panel ajax:toolkit and WebFormControls. now we want to upgrade the project and use ajax jquery Instead update panels and the ajax:toolkit. my Question is: what is the best way to do it? should i need to get the data on server convert it to json and render it on client(without the use WebFormControls. or on page load i have to use Web Form Controls and when user do change render it on the server.our project is developed with dot net 3.5 and w