Calling Codebehind funtion - Easy with Java Script

I was trying hard to call a function, written in .cs file to call it from the .aspx file using JavaScript or any other method finally I succeed and created this piece of code after a research... now want to share it with you people.

script function

 function callsub() {
        document.getElementById("Hidden1").value = document.getElementById("TextBox1").value
        document.getElementById("Button1").click();
    }
    function moveindex() {
        var rng = document.selection.createRange();
        rng.moveStart("character", 200);
        rng.select();
    }

asp:TextBox ID="TextBox1" runat="server" onkeyup="callsub()" onfocus="moveindex()">/asp:TextBox>
asp:Button ID="Button1" runat="server" Text="Button" style="display:none" OnClick="Button1_Click1" />

//cs function

   protected void Button1_Click1(object sender, EventArgs e)
    {
        Response.Write(DateTime.Now);
        TextBox1.Focus();
        TextBox1.Text = Hidden1.Value;
    }