Problem w/ Drop Down List PHP

[ryanbutler]

Hi,

This current problem of mine is driving me nuts, there has to a solution. I'm farily new to PHP and have a couple questions which hopefully can be answered. I have two files, contact.php contains a form, with a drop down list. When the user hits the submit button, they are directed toward tutorialcontact_result.php which catches any errors. If there is an error, on this page I provide a link back to contact.php. My first problem is: I'm trying to validate a drop down list using a regular expression as shown below:

if(eregi("[a-z | A-Z]+", $_POST['whichtutorial'])){
$d=true;
}else{
$d=false;
$message[]="Please select a tutorial.";
}

My drop down list contains characters, a hyphen, and numbers, the above is not working currently. I believe this regular expression only accounts for characters lowercase a-z and uppercase A-Z. Does anyone know what the regular could be?

Secondly, I want to retain the value the user selects from the drop down menu through sessions, which is currently working on my other form fiels except on the drop down list. The code below is my attempt which isn't working:

<select name="whichtutorial">
<?php echo $_SESSION['tutorial_memory']['whichtutorial'];?>
<option value="<?php echo $_SESSION['tutorial_memory']['definingsitemx'];?>null">--------------</option>
<option value="definingsitedwmx">Defining Site, DW MX</option>
<option Value="miscellaneoussubjectlines">Miscellaneous &mdash; Subject Lines</option>
</select>

If anyone knows a solution to the problem(s), it would be of great help. I'm stuck currently on this even through Google.

Thanks,

[ahundiak]

Can't help you on the regexp question.

But as far as options go, you need to add a selected="selected" attribute to the option that the user selected. Leave the exact code up to you though you will probably find it easiest to put all the options in an array and then foreach over the array to build the individual option elements.

[ryanbutler]

Seems like I keep getting the same answer on the drop down list, why can't a session just store the option the visitor selected? Using an array here instead seems to defeat the purpose of a session being used. I'm just confused that a PHP session can't retain this value, is there something I'm missing?

[ahundiak]

The session is used to retain the value of the option selected; not the html option string itself. You need to understand how html options work and then the need for the selected="selected" attribute will be clearer.

Remember that the only thing inside of $_POST is the value. Nothing in there will tell you that the value came from an html option.

[ryanbutler]

Alright...looks like I need to re-up on this then. I thought that since the input fields contained strings, the options worked the same way. Any reliable sources other than searching Google for hours on end?

I guess what I'm not understanding is if I put these values into an array like such:

<?php
 session_start(); 
$array = array( 
'htmlbasics' => 'HTML &mdash; Basics', 
'htmlframes' => 'HTML &mdash; Frames', 
'htmlforms' => 'HTML &mdash; Forms' 
); 

function form() 
{ 
    global $array; 

echo ' 
<form action="" method="POST"> 
<select name="whichtutorial"> 
'; 

foreach ($array as $key => $value) 
{ 
    echo '<option value="' . $key . '"'; 
    if (isset($_POST['whichtutorial']) && $_POST['whichtutorial'] == $key) {echo ' selected';} 
    echo '>' . $value . '</option>'; 
} 

echo '     
</select> 
<input type="submit" name="submit" value="submit"> 
</form> 
'; 
} 

if (!isset($_POST['submit'])) 
{ 
    echo 'select tutorial:<br>'; 
    form(); 
    echo '<a href="blah.php">blah</a>';
} 
else 
{ 
    echo ' 
    you selected ' . $array[$_POST['whichtutorial']] . '<br> 
    (note that your selection is retianed in the form below) 
    '; 
    form();
    echo '<a href="blah.php">blah</a>';
} 
?>

If I switch between test.php and blah.php, my selection doesn't stick.

One other question, how could one wipe a session out? What I mean, is on the contact.php page, I start the session. Going back and forth between the contact.php and tutorialcontact.php pages keeps the session alive. Only going to success.php will terminate the current session. The problem is when I press the reset button on contact.php, the values inside the text boxes are not resetting due to the session.

[ahundiak]

First off you are on the right track as far as the code goes. It may look ugly to you because you are still intermixing html and php. But once you start dividing the two then things will get cleaner.

Not sure what you mean by switching between test.php and blah.php. $POST will only have a value when the script is executed as a result of pressing a submit button in a form whose action is POST. It's up to your script to decide if the value is in $POST or if it's in $_SESSION or perhaps neither.

Use session_destroy to make a session go away.
http://us3.php.net/manual/en/function.session-destroy.php

[ryanbutler]

Not sure what you mean by switching between test.php and blah.php. $POST will only have a value when the script is executed as a result of pressing a submit button in a form whose action is POST. It's up to your script to decide if the value is in $POST or if it's in $_SESSION or perhaps neither.

That is what is confusing me, why would one use post over session. If the value is in $POST, then how do you transfer it over to $SESSION? I need the value in $SESSION from my understanding to extract the string value from the option tag. Am I correct or wrong here? Furthermore, from my reading the only way to retain the "state" of each form field from contact.php to contact_result.ph easily is to use a session. So should the above code checking the option tag have $SESSION instead of $_POST. It seems like this should be a relatively easy question to answer except for a new person.

I know that session_destroy will destroy a session, re-read my question. My issue is that the session isn't being destroyed on a reset of the button. How does the juggling of a session along with a javascript reset confirmation work hand in hand?

[ahundiak]

Not really sure how to make this less confusing. It's easy once you get the hang of things.

if (!isset($_POST['submit'])) 
{ 
    echo 'select tutorial:<br>'; 
    form(); 
    echo '<a href="blah.php">blah</a>';
} 
else 
{
    if (isset($_POST['whichtutorial'])) 
        $_SESSION['whichtutorial'] = $_POST['whichtutorial']; 
    else                                               

        $_SESSION['whichtutorial'] = 0; // Or some default value

// And then use $_SESSION for the rest
// Better yet, redirect back to the script
echo ' 
you selected ' . $array[$_POST['whichtutorial']] . '<br> 
(note that your selection is retianed in the form below) 
'; 
form();
echo '<a href="blah.php">blah</a>';
} 

[ryanbutler]

Hmm...alright, I'll take a look at the script in some more detail that you provided.