Execute a C# void from javascript function in aspx webform

I have a button that executes a delete action to a row in a database. I wrote a javascript function that creates a custom dialog box that allows users to select if they do want to delete the data. However, when I try to execute the private void from code behind inside javascript, it does not run. I have searched through a lot of websites and tried many ways suggested but have not succeed yet. Please help me.

(javascript with asp.net)

    <script language="javascript" type="text/javascript">
        function OnDelete(msg, myYes, myNo) {
            var deleteBox = $("#delete");
            deleteBox.find(".message").text(msg);
            deleteBox.find(".yes, .no").unbind().click(function () {
                deleteBox.hide();
            });
            deleteBox.find(".yes").click(myYes);
            deleteBox.find(".no").click(myNo);
            deleteBox.show();
        }
        function RunDelete() {
            var rvalue = '<%= rvalue.ClientID %>';
            OnDelete("Delete?", function yes() {
                document.getElementById(rvalue).value = "Yes";
            },
                function no() {
                    document.getElementById(rvalue).value = "No";
                });
            document.getElementById('<%=btn_del.ClientID %>').click();
        }
    </script>
    <style>
        #delete {
            display: none;
            background-color: #FFFFFF;
            color: #000000;
            border-radius: 12px;
            border: 2px solid #000000;
            position: fixed;
            width: 225px;
            height: 100px;
            left: 45%;
            top: 40%;
            margin-left: -100px;
            padding: 15px 25px 15px;
            box-sizing: border-box;
            text-align: center;
        }
 
            #delete button {
                background-color: #FFFFFF;
                display: inline-block;
                border-radius: 12px;
                border: 1px solid #000000;
                padding: 5px;
                text-align: center;
                width: 60px;
                cursor: pointer;
            }
 
            #delete .message {
                text-align: left;
            }
        .auto-style58 {
            width: 65px;
            text-align: right;
        }
        .auto-style59 {
            text-align: right;
        }
        .auto-style60 {
            width: 103px;
            text-align: center;
        }
    </style>
    <div id="delete">
        <div class="message"></div>
        <br />
        <button class="yes">Sure</button>
        <button class="no">Not yet</button>
    </div>

    <asp:Button ID="btn_del" runat="server" Font-Bold="True" Text="DELETE" Width="130px" UseSubmitBehavior="false" OnClientClick="return RunDelete();" OnClick="btn_del_Click" />

Code behind (C#)

    protected void btn_del_Click(object sender, EventArgs e)
        {
            DeleteData();
        }