Need help to create: ImageButton Click event tiggers Calendar pop up

I am writing a web page, on this web page there is a txtStart and txtEnd. Next to them I have Calendar ImageButtons. I would like to code it so when the ImageButton is clicked a calendar popup appears and when they select a date on the popup it goes away and the date is populated into the txt. Format MM/DD/YYYY. Can anyone help me? I have been looking online for hours now and only find solutions for C# users or for a seperate page all together. I am writing my code in VB and I cannot make new pages. Here is my web page code:
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="PSInventoryRelease.aspx.vb" Inherits="DigeControlCenter.PSInventoryRelease" %> <%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="TC" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DT ...