Dynamic forms

[Ogdan]

Hey everyone I was just wondering if it were possible to make dynamic forms that were either self posting or posted to another page. For example could i use the $_GET array to make a form on another page that added elements based on input from that form?

 

like so

 

<form action="Question7_process.php" method="get">

            please enter a number:

            <input type="text" name="number" value="" />

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

</form>

 

 

 

then use that number to make a form with how ever many input fields and have it SELF POST and pull the values off of the $_POST array? I'm having a problem and would love some input. Thank You

[mapleleaf]

Can you explain what you mean by self posting as you can easily make a form with the number of inputs put in the first form with a loop. But why would you want that to self post as you don't have anything inputted till the user adds something?

[Ogdan]

ok so here might be a better explanation so i want a user to enter how many numbers they would like to add, lets say the user inputs 4 then the form would either SELF POST or POST to another page with the 4 input fields, where the user would enter 4 numbers then the form would add them all up. The problem I am having is on the second page the only thing that is getting input to the $_POST array is the last number.

[roopurt18]

You can do this with a form that consistently reposts to itself.

 

You also need to be familiar with the concept of a state machine.  You can find plenty of material online about FSM (Finite State Machines).  The short of it is you create a machine (aka program) that has several states.  What it does depends on which state it is currently in!

 

<?php

define( 'STATE_INIT', 0 );
define( 'STATE_HAVENUM', 1 );
define( 'STATE_ENTERNUMS', 2 );

$state = array_key_exists( 'moveto', $_POST ) ? $_POST['moveto'] : STATE_INIT;
$state = in_array( $state, array( STATE_INIT, STATE_HAVENUM, STATE_ENTERNUMS, STATE_FINAL ) ) ? $state : STATE_INIT;
// By this point, $state is one of the three states

$errors = array(); // We might have errors
if( $state == STATE_HAVENUM ) {
    // Must confirm that the number is a number!
    $num = array_key_exists( 'num', $_POST ) ? $_POST['num'] : false;
    $num = is_numeric( $num ) ? ((int)$num) : false;
    if( $num === false ) {
        $errors[] = 'You did not enter a number!';
        $state -= 1; // Decrease state by 1
    }
}else if( $state == STATE_ENTERNUMS ) {
    // Must confirm all entered numbers are numbers!
    $had_err = false;
    $total = 0;
    if( array_key_exists( 'nums', $_POST ) && is_array( $_POST['nums'] ) ) {
        foreach( $_POST['nums'] as $v ) {
            if( ! is_numeric( $v ) ) {
                $had_err = true;
                break;
            }
            $total += $v;
        }
    }
    if( $had_err ) {
        $errors[] = "Fill out all fields with numbers!";
        $state -= 1;
    }
}


// Begin our form
$form = <<<EOT
<form method="post" action="{$_SERVER['REQUEST_URI']}" />
EOT;

if( $state == STATE_INIT ) {
    $moveto = STATE_HAVENUM;
    $form .= <<<EOT
        <p>
            <input type="hidden" name="moveto" value="{$moveto}" />
            How many inputs? 
            <input type="text" name="num" value="" size="3" />
        </p>
        <p><input type="submit" name="submit" value="submit" />
EOT;
}else if( $state == STATE_HAVENUM ) {
    $moveto = STATE_ENTERNUMS;
    $form .= <<<EOT
        <div>
            <input type="hidden" name="moveto" value="{$moveto}" />
            <input type="hidden" name="num" value="{$_POST['num']}" />
        </div>
EOT;
    for( $i = 0; $i < $_POST['num']; $i += 1 ) {
        $form .= <<<EOT
            <p><input type="text" name="nums[]" value="" size="3" /></p>
EOT;
    }
    $form .= <<<EOT
        <p><input type="submit" name="submit" value="submit" />
EOT;
}else if( $state == STATE_ENTERNUMS ) {
    echo "<p>The total is {$total}</p>";
}


$form .= "</form>";
if( count( $errors ) ) {
    echo '<p>You had errors:</p>';
    echo '<ul><li>' . implode( '</li><li>', $errors ) . '</li></ul>';
}
echo $form;
?>