页面代码：
1 <asp:DropDownList ID="ddlFolder" runat="server" SkinID="ddlSkin" AutoPostBack="false" OnSelectedIndexChanged="ddlFolder_SelectedIndexChanged">
2 <asp:ListItem Value="0">选项0</asp:ListItem>
3 <asp:ListItem Value="1">选项1</asp:ListItem>
4 </asp:DropDownList>
2 <asp:ListItem Value="0">选项0</asp:ListItem>
3 <asp:ListItem Value="1">选项1</asp:ListItem>
4 </asp:DropDownList>
JS代码：
1 document.getElementById("ddlFolder").value="0";//0为你要选中的项的value
