Posting to an ASP page

I'm integrating a Classic ASP app into a ASP.NET site.  The ASP app is for
creating, sending, and maintaining newsletters, so the only page the user sees
is the subscription page.  The .net site uses master pages, so I want to make
the subscription page a .net page.  That way the page doesn't get overlooked if
we make any changes to the master file.  

I know I can use a button control as the submit button and put the page it's
posting to in the PostBackUrl property.  However, the Classic ASP form string
looks like this:

<form onsubmit="return formvalidation(this)"
method="post" name="subform"
action="http://www.writeaprisoner.com/nmanagerpro/forms/optIn.asp"
target="blank"> 

I have the javascript functions.  How do I use them to validate the form fields
while posting?   How do I add the target="blank"?

Diane

Yes you can.  You could even make it so the button isn't visible until
everything is validated.

if your your function is called in code behind, that means the form has already
been submitted. 

there are 2 ways if you want to stop the button click from submitting the form:

1. write a javascript function instead of code-behind and call it before
submit.

2. use ajax to call your function in code-behind

if your your function is called in code behind, that means the form has already
been submitted. 

there are 2 ways if you want to stop the button click from submitting the form:

1. write a javascript function instead of code-behind and call it before
submit.

2. use ajax to call your function in code-behind

Ok, so I took the validation check out of the button click event and put it in
the page load event.  I verified through debugging that this runs first.  So if
the email address doesn't validate, can I stop the button click event from
happening?

Diane