Question

I want to send data from client and create it on server. So:
1) How can I get the total milliseconds count by JavaScript Date object?
2) How can I create .NET DateTime object by total milliseconds count?

Answer 1

You will have to use AJAX for this. Once you send the d.getTime() as explained by the other answer, parse it like this in your C# code behind:

if (!string.IsNullOrEmpty(Request.Form["milliseconds"]))
{
    long clientSideMS = Int64.Parse(Request.Form["milliseconds"]);
    DateTime past = new DateTime(1970, 1, 1);
    DateTime clientSideDate = past.AddMilliseconds(clientSideMS);
}

After this, clientSideDate will be the date on the client side.

Edit: using jQuery, posting the date is as simple as:

var now = new Date();
var ms = now.getTime();
$.post("Page.aspx", { milliseconds: ms.toString() } );