You were already told that the '=' does not belong there so fix that first.
And if you keep insisting on posting a mix of XPath and ASP then it is difficult to help, unless you at least exactly specify which value for instance request.Form("search_by") has.
My posted sample shows you how to check the number of nodes selectNodes returns so check that for instance in your code to find out how many nodes your XPath finds.

--
  Martin Honnen
  Microsoft MVP - XML

I have already try like this:

path="form/description[<% request.Form("search_by")%>,'<% request.Form("txtSearch")%>']//*";

I change "=" become ","

but it still error...
 Error Said that "unexpected "," "

If I remove "," the result does not show

I use ASP code inside that because I want to get the value from the text field.

Either this for an exact match:

path="form/description[<%= request.Form("search_by")%>='<%= request.Form("txtSearch")%>']//*";

or this for a 'like' match:

path="form/description[contains(<%= request.Form("search_by")%>,'<%= request.Form("txtSearch")%>')]//*";



/- Sam Judson : Wrox Technical Editor -/

In
the contains is missing so you need
You can use ASP if you need but if you come to a forum telling others that the XPath expression does not work against your posted XML then you need to explain which values those ASP expression yield to allow others in the forum to decide where the problem is.

--
  Martin Honnen
  Microsoft MVP - XML

This is getting ridiculous. The XPath syntax isn't

form/description[title, 'value']

it is

form/description[contains(title, 'value')]

Just stop and think for ten minutes(*) next time you get an error message - or preferably before you put your hands on the keyboard.

(*) I see Sam said "for a moment", but in your case I would recommend longer than that.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

I try this one:

and it still error and said that unknown method...

<%= request.Form("search_by")%>
to get from drop down menu which is named "search_by"

<%= request.Form("txtSearch")%>
to get from text field which is named "txtSearch"

in dropdown menu there are some values like: type, author, dates, title, etc

In text field, users can type the keyword that they want to search.

if I do not use ASP code, it should look like this:

or

or

so, because I wanna get "year, type, author" from the drop down menu, I use ASP code.
And, because I wanna get the value from the user that has been typed,
I also use ASP code to get it.


I still have no idea. Or maybe I ask this problem to ASP forum?
Am I in right place to ask my problem?

Thank you all for your helping


:)

If you are using MSXML 3 to evaluate the XPath expression you need to make sure you set
before you evaluate XPath expressions with selectNodes or selectSingleNode.

--
  Martin Honnen
  Microsoft MVP - XML