How to transfer from javascript to c#

[David]

Hi, pardon me for my english.

I add a ActiveX in my asp.net and I can get it's return and put it in
my TextBox.
But I need the value transfer to my class, like this:

// test.aspx
function ServerReturnMessage()
{
message = AniAliActiveX.GetServerReturnMessage();
document.getElementById("textBox1").value = message;
}

// test.aspx.cs
private GetServerReturn ( string str )
{
// write it to DB
...
}

I use TextBox1_TextChanged, but it's value can not transfer to the
method.

Thanks for your kind advice, David.