with javascript how to display the list in the same page without reload.
Using XMLHttpRequest or jQuery AJAX, you can update server side and then create needed controls on client side. Once you have the controls created, add them to the placeholder of 'to-do' list.
Refer:
Have a look at these for XMLHttpRequest or jQuery AJAX:
XMLHttpRequest Object[
^]
Invoke Server Methods From Client Side Using jQuery AJAX in ASP.NET[
^]
For creating controls on client side:
Use jQuery:
http://api.jquery.com/append/[
^]
http://api.jquery.com/html/[
^]
Or raw JavaScript, like:
var inp = document.createElement('input');
inp.name = "control1";
inp.type = "text";
inp.id = "control1";
document.getElementById("yourcontainer").appendChild(inp);