I have a drop down that is populated from an access database. This drop down is a list of databases the user can select one at a time to few discussions. The drop down is populated from the Tbl_Database which has a filed names Db_ID and DbName. How do I make it subit once the selection is made without using a button?

Code I have:
<table width="770" border="1" cellspacing="0" cellpadding="0">
<tr>
<td><form action="dbchange.asp" method="get" name="db_drop"><select size="1" name="DbName" style="color: #003366; font-style: normal; font-family: verdana; font-weight: normal; font-size:10px">
<% Set oRs = oConn.Execute("SELECT * FROM Tbl_Databases"%>
<% Do While Not oRs.EOF 'define the listbox options %>
<OPTION VALUE="<%= oRs("DbName" %>"> <%= oRs("DbName" %>
<% oRs.MoveNext %>
<% Loop %>
</select</form></td>
</tr>
</table>