Reset DropDownList selected value on PostBack using jQuery

<asp:DropDownList ID="productNameDDL" CssClass="form-control" DataSourceID="" runat="server" OnTextChanged="productNameDDL_TextChanged" AppendDataBoundItems="true">
</asp:DropDownList>

dropdownlist load data from database and use a button to save data to database

<asp:Button ID="btnAdd" CssClass="btn btn-primary  hvr-grow-shadow" Font-Size="Large" Width="150px" runat="server" Text="Submit"  OnClick="btnAdd_Click" />
                   

and 

$(function () {
   $("#btnAdd").bind("click", function () {
       $("#productNameDDL")[0].selectedIndex = 0;
   });
});