DropDownList event

Question

DropDownList event OnSelectedIndexChanged working fine on my local machine but when i publish my code on server it does not work so plz help me..

 

<asp:DropDownList ID="ddlTest" runat="server" OnSelectedIndexChanged="OnSelectedIndexChangedTest" AutoPostBack="true" CssClass="dropdown" Width="200px">

</asp:DropDownList>