How to call function in code-behind in c# with jquery?

Question

How to call function in code-behind in c# with jquery?

I have this code behind :

protected void btn_Click(object sender, EventArgs e)
{
if (btn != null && btn.Checked)
{
Response.Redirect(string.Format("get.aspx?a={0}&b={1}",
a.SelectedValue, b.SelectedValue));
}
}

And I have a Checkbox :

<asp:CheckBox ID="btn" runat="server" Checked="false" />

I am tryong to call that function btn_Click in jquery :

$(document).ready(function () {
if ($('#btn').is(':checked')) {
$(button).trigger("btn_Click");
}
});


But not worked!!!

Why? Thanks.