The following example demonstrates a basic page that has form based flow control, takes input from the user to put into the database and then displays the results. This simple example can be extended to perform more substantial operations by adding a few more inputs, buttons and states.

Things to look at:

get_keyword is used to extract parameters from the form that were posted last time
the current mode is determined by the value of the submit parameter
straight HTML can be inline with VSP flow control which is how the whole page is contained in an if condition.
<HTML>
<HEAD></HEAD>
<BODY>
<form method="POST" action="simpletest.vsp">

<?vsp
-- assumes that you have a table db..test_table(txt varchar(2000))

-- declare variables for use
declare _mode varchar;
declare _theValue varchar;
declare _stmt varchar;

-- get the current mode and continue accordingly
_mode := get_keyword ('submit', params, 'default');

if (_mode = 'Submit')
{
  -- if a submit was detected then insert the value into the DB
  _theValue := get_keyword('myTxtBox', params, 'no comment');
  _stmt := sprintf('insert into db..test_table(txt) values(\'%s\')', _theValue);
  exec (_stmt, '', '', '', '', '', '');

?>
   <P>Thank you for your submission.</P>
<?vsp
} else {
?>
   <DIV>
   <DIV>Simple test form, enter some text and hit submit.</DIV>
   <DIV><textarea name="other" rows="3" cols="64"></textarea></DIV>
   </DIV>

   <DIV><input type="submit" name="submit" value="Submit"></DIV>

   <HR />
   <H2>Values currently in table</H2>
   <TABLE>
   <?vsp
   for (select txt from db..test_table) do
     http(sprintf('<TR><TD>%s</TD></TR>', txt));
   ?>
   </TABLE>

<?vsp
}
?>
</form>
</BODY>
</HTML>

You may wish to offload some of the functionality of the page to a stored procedure and call that from that page. You may do this to improve readability of the page or there may be a series of functions that you repeat such as displaying a particular table in some format.

You could used a procedure as follows:

create procedure table_list()
{
   http('<H2>Values currently in table</H2>');
   http('<TABLE>');
   for (select txt from db..test_table) do
      http(sprintf('<TR><TD>%s</TD></TR>', txt));
   http('</TABLE>');
};

You could then call this in instead of defining the query and table layout as above.

The aspects of VSP are explained in more detail in the following sections.