[RESOLVED] Dynamic dropdowns - first option should affect the second

jinky32

Hi guys, I'm really hoping someone can help me - i've been searching for ages but can't seem to find an answer.

I'm dynamically creating a dropdown menu from values stored in a db and I want the option chosen in the first menu to affect the options that the user sees in the second. The first menu contains a list of vegetables (e.g pea) and when a user selects one they should see only particular strains of that veg (hurst, avola etc are types of pea)

The code I've written is (with a database connect above this)

<form action="<?php echo $_SERVER['PHP_SELF']?>" method="post">
	<p>Vegetable Type <select name="vegetable"> //start of veg drop down
		<?php
	$query="SELECT vegetable_pk, vegetable_type FROM vegetables"; //query db
	$result=mysqli_query($dbc, $query) or die("Query failed: " . mysqli_error($dbc));  //run query
		while($row=mysqli_fetch_array($result)){ //loop thu results
			echo "<option  value=\"$row[vegetable_pk]\">$row[vegetable_type]</option>\n"; //echo out results
		}
		?>	
	</select></p> 

<p>Vegetable Type <select name="vegetable"> 
	<?php
$query="SELECT name_pk, name FROM names WHERE vegetable_pk='$row[vegetable_pk]'";
$result=mysqli_query($dbc, $query) or die("Query failed: " . mysqli_error($dbc));
	while($row=mysqli_fetch_array($result)){
		echo "<option value=\"$row[name_pk]\">$row[name]</option>\n";
	}
	?>
</select></p>

In the query for the second menu I've tried to use $row[vegetable_pk] which is set in the first. I'm guessing it's not working because the value isn't actually being submitted. Is that right? Is there any way I can get the second menu to rely on the first without requiring the user to hit a submit after the first menu?

Many thanks for any help! 🙂

djjjozsi

try this example:

http://php-ajax-code.blogspot.com/2007/07/ajax-triple-dropdown-with-states-cities.html

jinky32

that looks really interesting - many thanks! It's a bit late to try this evening bu I'll take a look tomorrow. Thanks for the help!🙂

jinky32

hi djjjozsi. Thanks again for the script. I've been able to make a few changes to it and it works exactly how I would like it to!

<?
//set IE read from page only not read from cache
header ("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header ("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header ("Cache-Control: no-cache, must-revalidate");
header ("Pragma: no-cache");

header("content-type: application/x-javascript; charset=tis-620");

$data=$_GET['data'];
$val=$_GET['val'];

//set database
require_once('./includes/dbc_connect.php');


if($_POST['submitted']){
	$errors=array();

if(empty($_POST['vegetables'])){
	$errors[]="You need to select a vegetable";
	} else {
	$veg=$_POST['vegetables'];
	}

if(empty($_POST['vegtype'])){
	$errors[]="You need to select a vegetable type";
	} else {
	$vegtype=$_POST['vegetype'];
	}

if(empty($errors)){
	$query="INSERT INTO sowings (vegetable_fk, name_fk, user_fk) VALUES ('$veg', $vegtype, '7')";
	$result=mysqli_query($dbc, $query) or die('there was a problem'. mysqli_error($dbc));
	if($result){
		echo "info added to db";
	} else {
		echo "there was a problem with the query: $query";
	}
}



}

if ($data=='vegetables') {  // first dropdown
  echo "<select name='vegetables' onChange=\"dochange('vegtype', this.value)\">\n";
  echo "<option value='0'>==== choose veg ====</option>\n";
  $query="SELECT vegetable_pk, vegetable_type FROM vegetables";
  $result=mysqli_query($dbc,$query);
  while($row=mysqli_fetch_array($result)){
       echo "<option value=\"$row[vegetable_pk]\" >$row[vegetable_type]</option> \n" ;
  }
} else if ($data=='vegtype') { // second dropdown
  echo "<select name='vegtype' >\n";
  echo "<option value='0'>====choose veg type ====</option>\n"; 
  $query="SELECT name_pk, name FROM names WHERE vegetable_pk= '$val'";                

  $result=mysqli_query($dbc,$query);
  while($row=mysqli_fetch_array($result)){
       echo "<option value=\"$row[name_pk]\" >$row[name]</option> \n" ;
  }
}
echo "</select>\n";
echo '<input type="submit" name="submit" value="add details!" />
	<input type="hidden" name="submitted" value="TRUE" />
	</form>';

?>

Apart from getting two 'submit' buttons :p I am having a problem getting the selected values from the two dropboxes into a db. I know I'm using POST on my validation whereas the script seems to be using GET, but even changing this doesn't seem to help.

Can you (or anyone) offer any advice about how to get the values submitted to db??

Many thanks!

djjjozsi

there are two things you need to understand 🙂

The two dropdown is communicating with the PHP file via $_GET method,

but its up to you to decide the method how your form will send the selected values from your form.

And i suggest use $_POST method. Then your can test if the POST array is empty or not:

if(!empty($_POST))
{
print_r($_POST);
/* JUST FOR TESTING THE VALUES!!!  */
die("Hard");
}

And read my signature about the queries 🙂

jinky32

great! thanks again for your help 🙂

djjjozsi

Your welcome,
if its solved now then don't forget to set this thread as resolved.

Hello, jjozsi.