Apr 06, 2020 08:40 AM|samwu|LINK
<input type="button" id="btnsend" class="chtbtn" value="Send" onclick="insert.aspx();" />
var date = document.getElementsById('<%=txtdate.ClientID%>').value;
I tested your code and found some mistakes.
First the insert method should be onclick = "insert ()".
And when you get the date, there is an extra 's' in getElementById.
Please try to use F12 to view and debug your code.
More information about how to use the F12 Developer Tools you can refer to this link: