二级分类首次显示不出来

<%
Set b_news=Conn.Execute("Select * From [BigClass]")
Response.Write "<select name=BigClassName onChange='changelocation(document.myform.BigClassName.options[document.myform.BigClassName.selectedIndex].value)'>"
If b_news.Eof and b_news.Bof Then
Response.Write "产品大类!"
Else
Response.Write "<option value='" &Trim(b_news("BigClassName"))& "|" &b_news("EnBigClassName")& "'>" &Trim(b_news("BigClassName"))& "(" &Trim(b_news("EnBigClassName"))& ")</option>"
Dim selclass
selclass= b_news("BigClass")
b_news.MoveNext
Do until b_news.Eof
Response.Write "<option "
Response.Write " value='" &Trim(b_news("BigClassName"))& "|" &b_news("EnBigClassName")& "'>" &Trim(b_news("BigClassName"))& "(" &Trim(b_news("EnBigClassName"))& ")</option>"
b_news.MoveNext
Loop
End if
Response.Write "</select>"

Set s_news=Conn.Execute("Select * From [SmallClass] Where BigClassName='" &selclass& "'")
Response.Write "<select name=SmallClassName>"
If s_news.Eof Then
Response.Write "产品小类"
Else
Response.Write "<option value='0' selected>产品小类</option>"
Do until s_news.Eof
Response.Write "<option value='"&Trim(s_news("SmallClassName"))&"|"&s_news("EnSmallClassName")&"'>" &Trim(s_news("SmallClassName"))& "(" &Trim(s_news("EnSmallClassName"))& ")</option>"
s_news.MoveNext
Loop
End if
Response.Write "</select>"
Response.Write "(请先选择产品小类)"
%>