How to create and retrieve cookies using ASP
Cookies are easy to create and retrieve using ASP.
They can be used to remember things about a user when they come back to your site. Cookies
expire after a certain amount of time which you can set. Also, the clients browser must
have cookies enabled for them to work.
Here is a very simple
example of creating a cookie called "MYCOOKIE" with a key called
"BgColor" and setting the cookie to expire in one year. In this example
there is only one key, but cookies can have multiple keys.
<%
Response.Cookies ("MYCOOKIE")("BgColor") = "Blue"
Response.Cookies ("MYCOOKIE").Expires = DATE + 365
%>
If you don't set the "expires" time the cookie will expire right away so don't
leave that part out.
Please Note: You must create the cookie before the HTTP headers are written to the client browser. Basically that means you need
to create cookies before the <HTML> tag on your page.
However if you turn on buffering like so <% Response.Buffer = True %>
then you can create the cookie wherever you want within your code because when buffering
is turned on no information is written to the client browser until the all the code is
finished running. The <% Response.Buffer = True %> needs to go right under the
<%@LANGUAGE="VBSCRIPT"
%> on your page.
Also don't use underscores or other
strange characters when naming your cookies because they may not work.
Here is are examples of retrieving the cookie.
Do this if you don't care if the cookie exists or not.
<%
Response.Write(Request.Cookies ("MYCOOKIE")("BgColor"))
%>
Do something like this if you want to check first to see if the cookie exists which is
usually a good idea.
<%
If Request.Cookies ("MYCOOKIE")("BgColor") <> "" Then
Response.Write(Request.Cookies ("MYCOOKIE")("BgColor"))
Else
'you could do something like ask them to pick a BgColor and then set the cookie again
'or you could just give them a default value for the Bgcolor since they don't have
a cookie
End If
%>
When you create a cookie the info is saved on the clients computer.
With IE a text file is created in the cookies directory of the clients computer. It keeps
track of the cookie. If they are using netscape there is a file called cookies.txt where
the cookie info piles up. Either way if they delete the cookie info the cookies will be
gone when they return to your site.
There is a lot more to using cookies but this is the basic info you need to know to create
and retrieve them.
|
