Checking Pages For No Data Posted
Users of you site sometimes get a nasty error message when they somehow manage to get to
the page a form posts to without actually posting to the form or sometimes just a page
that is linked to from another page with querystring info like so. ?ID=236454
If the page doesn't get that info it causes a big error to show up which makes
things look
bad.
This problem usually happens when a page is looking for an ID or some
other info and the user used a bookmark or search engine link to get to the page. Then the
info the page needs is missing and this ends up causing the SQL statement or something
else to fail giving an error message.
You can control the situation by checking to see if any data was posted and then show a
custom error message or perform some other action like redirecting them to the page you
want them to be at.
In the following 3 examples a message is simply shown on the screen.
Put this code directly under the
<%@
LANGUAGE="VBSCRIPT" %>
For a form using the POST Method
<%
If Request.Form = "" Then
Response.Write("<p align=""center""><font
face=""Arial"">There Was An Error.<br>" & vbCrLf)
Response.Write("No Data Was Posted.</font></p>" & vbCrLf)
Response.End
End If
%>For a form using the PUT or GET Method.
This also works for a page that just gets Querystring info from a link.
ex:)
?ID=236454
<%
If Request.Querystring = "" Then
Response.Write("<p align=""center""><font
face=""Arial"">There Was An Error.<br>" & vbCrLf)
Response.Write("No Data Was Posted.</font></p>" & vbCrLf)
Response.End
End If
%>
To cover any of the situations above the examples
below should work . There
are shorter ways to do this.
<%
IsData = 0
If Request.Form <> "" Then IsData = IsData + 1
If Request.Querystring <> "" Then IsData = IsData + 1
If IsData = 0 Then
Response.Write("<p align=""center""><font
face=""Arial"">There Was An Error.<br>" & vbCrLf)
Response.Write("No Data Was Posted.</font></p>" & vbCrLf)
Response.End
End If
End If
%>
or
<%
IsData = "No"
If Request.Form <> "" Then IsData = "Yes"
If Request.Querystring <> "" Then IsData = "Yes"
If IsData = "No" Then
Response.Write("<p align=""center""><font
face=""Arial"">There Was An Error.<br>" & vbCrLf)
Response.Write("No Data Was Posted.</font></p>" & vbCrLf)
Response.End
End If
End If
%>
Article Update: 2/2/2002
Those this is still an interesting article the truth is you should really be
checking for variables that you expect a a page to be receiving variables individually
and deal with the situation accordingly.
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