form sequence trouble

botsguy

I there, I have sequence of forms which require the user to enter some stuff at each step. The last step requires the user to confirm all the info they have entered. If they have made an error they are told to hit back on there browser to modify any mistakes.

Question 1: how can I ensure that this info remains in the input fields in the form when the user hits back.

Once the user has confirmed all the input they are taken to another page. From this page they can go 'back' on there browser and undesirably resubmit info.

Question 2: After they have confirmed the info How can I stop the user from going back to the process page and the other pages and accidently resubmit informaiton creating duplicate record in my db. (my key here based on a timestamp so this is will happen at the moment)

Cheers,

James

nova

hm...

Question 1:
In the back button link, put all the variables from the previous form. So example:

<?PHP

print"
<FORM ACTION=next.php METHOD=post>
<INPUT TYPE=text NAME=user VALUE=$name>
<INPUT TYPE=submit NAME=next VALUE=next>
</FORM>
";

?>

So when the user hits next, the php will have a variable called $name with whatever the user put as a name. In the back button on the next page put this link:

<?PHP

<A HREF=previous.php?name=$name>Back</A>

?>

This is how it works, when previous.php (page 1) loads, $name is null, so the text area is empty, but if you hit back from page to, $name is equal to whatever the user put in when he pushed next from page 1. So if he put in fred, then pushed next, then back, the text boc name will have the text fred in it.

Question 2 comming

nova

Question 2:

Use the same idea as above, lets use a variable called $var for varified. Now, when the user pushes next, it runs through the varification proccess, and if it failts, set $var to 0, but if it passes set it to 1, and load page 2.

Now in page 2's back button, put this code:

<?PHP

if ($var != 1) {
  print"<A HREF=previous.php?name=$name>back</A>";
}else{
  print"back";
}

?>

This checks if the previous page was varified, if it was, then the back button is just text, without a link. If it has not been varified, the back button is a link and the user can click it.

Weedpacket

Alternative. Use session variables.

On each form start off the script with
session_start();

Then as the form details come in, store them in $SESSION['name of field'];. Once that has been done they'll be available (as $SESSION['name of field']) on any other page which starts with session_start().

No hidden fields are needed in the form, and there is no need to decorate the URL for the back link.

When you go to display a form, check the appropriate session variables to see if they're set, and if so, write the data back into the appropriate spaces.

That handles backing up.

For preventing double-posting: On page 1 of the form, start the session, and generate a unique string (md5(uniqid("")) should do the trick) and store that in a session variable. When the form details are stored in the database, this and the session id (session_id()) will be stored in the database as well.

Before doing the insertion, check to make sure that there is not already an entry with the same session id and the same unique string. If there are, then this is a duplicate submission. (The unique id is needed if there is the possibility of two separate form posts in the course of the same session.)

After the insertion has been made, unset all the session variables, so that future form-fillings can go ahead unhindered.

botsguy

thanks weedpacket thats the solution I was looking for.