Maintain Scroll Position on PostBack in ASP.Net

How to stop going page on top ASP.Net

I have (first)-DropDownList On change-index Dropdownlist2 fill

Everything is working but when the index change page scroll on top then user need to come down on that place when he was before selecting first DropDownList.

Please help 

<tr>
    <td style="vertical-align: middle">Degree Status</td>
    <td>
        <asp:DropDownList ID="cboDegreeCompleted" runat="server" CssClass="chzn-select ddst" AutoPostBack="true" Width="50%">
            <asp:ListItem Text="Select" Selected="True" Value="0"></asp:ListItem>
            <asp:ListItem Text="Complete" Value="Complete"></asp:ListItem>
            <asp:ListItem Text="In Progress" Value="In Progress"></asp:ListItem>
        </asp:DropDownList>
    </td>
</tr>

Protected Sub cboDegreeCompleted_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cboDegreeCompleted.SelectedIndexChanged
    If cboDegreeCompleted.SelectedValue = "In Progress" Then
        cboDegreeProgress.Enabled = True
    Else
        cboDegreeProgress.Enabled = False
    End If
End Sub