generating stuff when drop down selected...if()?

adamlloyd

Righty ho, read loads of stuff about populating drop downs and wot not, but can't find what i want to do, plus being a php noob, feel a weener asking.....

I've got a drop down, populated from my database, containgin payment types:

Cheque
Credit Card
Debit Card
Invoice

Depeding on the selection made, i want to display different stuff....

This is all held in a big form with a load of other stuff, and i don't want to have to send the user to a diff page with just this bit on in a form of its own.

I think i need something like this:

<my payment option drop down>
<?php
code that populates the select field
$result=mysql_query("SELECT paymentkind FROM payment_info") or die("Nada happening here payment_info....");

// put data into drop-down list box
$option_block_paymentkind = "ad";
while ($row = mysql_fetch_array($result))
{
$i = $row["paymentkind"];
$option_block_paymentkind .= "<OPTION value=\"$i\">$i</OPTION>";
}
echo("<SELECT name=payment_info>$option_block_paymentkind</SELECT>*");
?>
</my payment option dropdown>

<stuff generated/displayed depending on drop down>
if drop down = 'Cheque'
then display this

else if drop down = 'Credit Card'
then display this

else if drop down = 'Debit Card'
then display this

else if drop down = 'Invoice'
then display this

end if
</stuff generated/displayed depending on drop down>

Any ideas?

I'm sure there are a million posts asking this question, i have to admit to only trawling though 18 pages, then searching and finding only a few returns.....containing drop down population

sijis

well, if you want the user to see the form immediately after he/she selects a particular payment option (without refreshing the current page or going to another php page), then you will want to use Javascript.

I don't know how to explain this, but PHP doesn't show 'new' stuff on a page until the page is refreshed because the PHP code needs to be interpreted by the server so the user sees the 'final' output.
Again if you want to see changed immediately, without refreshing the current page, you'll need Javascript.

as for your logic, it does make sense. It would only really work if once the user clicks on a payment type and the current page (user is on) is called with a passing post arg.

payment_type.php

<form method=post action=<?php echo $_SERVER['PHP_SELF']; ?> >
// drop down menu populated from DB.
// pay_type == credit, cash, etc.
</form>
<?php
$payment_type = $_POST['pay_type'];
if($payment_type == "credit"){
  //show this form
} elseif($payment_type == "cash"){
  // else show this form.
} else{
  // user is has NOT selected their 
  // payment type.
}
?>

hope i didn't confuse you.

adamlloyd

Yeah cheers for the reply, been using asp for a year or two, on and off, and yep had wondered about javascript for it, but am crap and get confused with javascript, hence the post.

Sijis in your reply you posted what to me, looks like a form calling itself, nothing new, but can i do that within a form on a page, where the main form is directed at another page...? (doubting myself here)

<form name=main action=update.php>
<form method=post action=<?php echo $SERVER['PHP_SELF']; ?> >
// drop down menu populated from DB.
// pay_type == credit, cash, etc.
</form>
<?php
$payment_type = $POST['pay_type'];
if($payment_type == "credit"){
//show this form
} elseif($payment_type == "cash"){
// else show this form.
} else{
// user is has NOT selected their
// payment type.
}
?>

main form submit button
main form reset form button
</form>

good sig - left handed - we are the blessed few

sijis

just change the the action in the <form> tag, which tells the form where to send the data to.

your_form.php

<html>
<form name=main action=update.php>
<form method=post action=<?php echo $_SERVER['PHP_SELF']; ?> >
// drop down menu populated from DB.
// pay_type == credit, cash, etc.
// submit buttons and such
</form>
</html>

update.php

<?php
$payment_type = $_POST['pay_type']; // same as Request.Form("pay_type")
if($payment_type == "credit"){
//show this form
} elseif($payment_type == "cash"){
// else show this form.
} else{
// user is has NOT selected their
// payment type. Show error or something
}
header("Location: http://url.com/"); // similar to Response.Redirect or Server.Transfer
?>

I get confused with javascript too. It should be easy, but i somehow never get it. I've also used ASP for about 1-2 year on and off... its easy to use it, but i'm beggining to like PHP much better.

well, of course you can put that inside the same page inside the <form> tags. just make sure you put the conditions between the <form></form> tags.

The reason I was calling the same page is so that the other input fields for the form would show in that page, that way you just don't get that "list all by itself" (as you stated). But the good thing about it, you can pass a hidden value (via <input hidden>) and see if the user has selected a pay_type and inputted some data before you redirect them to the confirmation and/or input data into the db. But i find it always much easier to use a seperate file when getting data from forms.

and yes, the left-handed are blessed 🙂