Forms and Form Data

Paramaters with Perl CGI

• Now that we have built the form, we must handle the results of the user inputting information and hitting return.
• Since we did not define an action for the form we declared, it will default to calling the same script that was used to generate the form page, just with the users supplied values filled in for the fields.
• The Perl CGI construct to extract the information from the web field we defined on the previous page would be:
  

  # Now conditionally report what the user typed in previously.
  
  # If this is not the first time into the script...
  if ($query->param()) {
      # Extract out whatever the contents of our field were.
      my $textInput = $query->param(-name=>'TextfieldOne');
  
      # Generate our output
      print $query->hr();
      print $query->p('The text you previously entered was:'), $query->br();
      print $query->em({-align=>'center'}, $textInput);
      print $query->hr();
  }
  

• Note that the variable names are relatively independent, but the fieldname (in this case TextfieldOne) is constant.
• Note also that we are detecting if this is the first time into the form by looking to see if there are any supplied arguments. If not, then this is the first time into the form, and we should just render the form. If there are supplied arguments, then the user must have entered data into the form and hit return, so we should display the results with their entered data. We have carried state along, complete with values.