Popup response linked with C# function

Question

I'm trying to call a JavaScript function with a popup. If user click on "Ok", it calls a C# function. In my case, the pop up is functioning but when I click "Ok" it not redirect to C# function. How to fix this?

 

<script type = "text/javascript">

function Confirm() {

var confirm_value = document.createElement("INPUT");

confirm_value.type = "hidden";

confirm_value.name = "confirm_value";

var noTel = document.getElementById("offcell").value;

var msg = document.getElementById("textarea-1").value;

alertify.confirm('PREVIEW MESSAGE', "To:" + noTel + "<br>Message:" + msg, function (e) {

confirm_value.value = "Yes";

document.forms[0].appendChild(confirm_value);

//__doPostBack('sms');

}, null).set('labels', { ok: 'Confirm', cancel: 'Cancel' });

}

</script>

 

The button that call JavaScript:

 

<asp:button runat="server" OnClick="Button1_Click" style="margin: 15px 22px;" type="submit" id="Button14" value="Login" Text="Send" CssClass="send blockbtn" name="send" OnClientClick="Confirm(); return false;"></asp:button>

 

The C# function :

 

protected void Button1_Click(object sender, EventArgs e)

{

if (Request.Form["confirm_value"] == "Yes")

{

Response.Redirect("Default.aspx");

//ClientScript.RegisterStartupScript(this.GetType(), "script", "document.location.href='/default.aspx';", true);

}

}