Add data to an ASP text box OnChange of a DDL

Fill in data into an ASP form text box OnChange of a DDL 2 minutes ago|janehollin|LINK        
<div> I have a table (Access database) like this
Field1 – Field2 – Field3 - Field4.
With data like this
Field1  Field2  Field3   Field4 ABC     XYZ      MNO     FGH RST      XYZ     QWE        CVB
I have an ASP form with a dropdown list like this
<asp:DropDownList id="DDL1" runat="server" DataSourceID="AccessDataSource1" DataTextField="Field1" ...