[SOLVED] PHP / JS Confusion

[bluebyyou]

So I am ussing PHP and two while loops to populate two separate drop down menus in my from from information stored in my DB. That works no problem. However I want to be able to change which options are desplayed in the second menu based on what is selected in the first. I have definately seen this done on websites before.  Anyways, can someone point me in a direction for me to start figuring this out, my JavaScript for dummies book isnt helping me.

 

Here is what I am working with...(ignore the js code, i just cut and pasted from another script I wrote to try and get started.)

<?php include("includes.php");

if (isset($_POST['submit'])) 
{ 
$today = date("Y-m-d");
$query = sprintf("INSERT INTO Posting (postdate,type,subtype,price,title,description,email,reply) 
                  VALUES ('%s','%s,'%s','%s','%s','%s','%s','%s')",
			  $today, $_POST['type'],$_POST['price'],$_POST['title'],$_POST['description'],
                  $_POST['email'],$_POST['reply']);

dbcon($query); // <-- database connection function located on includes.php
echo "upload success.";
unset($_POST['submit']);
}
else
{?>

<?php include("header.php"); ?>
<SCRIPT LANGUAGE="javascript" TYPE="text/javascript">
<!-- Hide from browsers that do not support JavaScript

function update_subtype() 
	{
	var update=yes
	document.writeln("hi")
	}

function display_subtype()
  		{
    	//var formSalary = document.form1.salary;
   		 var type = document.getElementById("subtype");
    	type.style.visibility=(document.form1.comp[0].checked)? "visible" : "hidden";
  		}

 -->
</script>
<form action="<?php echo $_SERVER['PHP_SELF'] ?>" method="post">
Posting Type<select name="type" onChange="update_subtype()">
<option value="0">Select One..</option>
<?php 
$query = "Select * FROM PostingType";
dbcon($query);

while ($row = mysql_fetch_array($result))
{
extract($row); ?>
<option value="<?php echo $key; ?>"><?php echo $name; ?></option>
<?php } ?>
</select><br>


<?php
$script = 1;
$query2 = "Select * FROM PostingSubType WHERE ptype= $script";
dbcon($query2); ?>

Posting Sub Type<select name="subtype" >
<option value="0">Select One..</option>
<?php

while ($row = mysql_fetch_array($result))
{
extract($row); ?>
<option value="<?php echo $psubtype; ?>"><?php echo $postingsubtype; ?></option>
<?php } ?>

</select><br><br>
Title<input name="title" type="text"><br>
Price<input name="price" type="text"><br><br>
Description<br>
<textarea name="description" cols="40" rows="4"></textarea><br><br>

Email<input name="email" type="text"><br>
Verify<input name="vemail" type="text"><br><br>

<input name="reply" type="radio" value="0" checked>Reply to my E-Mail<br>
<input name="reply" type="radio" value="1">Do not show my e-mail<br><br>

Upload image  (Coming Soon..)<br>
<input name="h" type="text" disabled><input name="browse" type="button" disabled value="Browse..."><br><br>

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

</body>
</html>
<?php } ?>

 

//includes.php
<?php

/* function dbcon stores the database connection information and
   the connection functions */

/* $result must be handled on each individual page.
   for example: $row = mysql_fetch_array($result) .. */
function dbcon($sql) 
{
$host = "*";
$user = "*";
$password = "*";
$database = "*";

global $result;

$connection = mysql_connect($host,$user,$password) or die ("couldnt connect to rockypages server.");
$db = mysql_select_db($database, $connection) or die ("couldnt select rockypages database.");
$result = mysql_query($sql) or die ("Couldn't execute query.");

return $result;
}

function dbcon2($sql2) 
{
$host = "*";
$user = "*";
$password = "*";
$database = "*";

global $result2;

$connection = mysql_connect($host,$user,$password) or die ("couldnt connect to rockypages server.");
$db = mysql_select_db($database, $connection) or die ("couldnt select rockypages database.");
$result2 = mysql_query($sql2) or die ("Couldn't execute query.");

return $result2;
}

/* This Function takes the numerica data from the PostingType Table 
   and converts it to the corresponding text. */ 
   
/* $input is the $key field in the database */
   
function posting_type($input)
{
$switch = $input;
switch ($switch)
{
case "1":
	$output = "For Sale";
	break;
case "2":
	$output = "Jobs";
	break;
case "3":
	$output = "Community";
	break;
case "4":
	$output = "Housing";
	break;
case "5":
	$output = "Services";
	break;
}
echo $output;
}

function posting_subtype($input)
{
$switch = $input;
switch ($switch)
{
case "1":
	$output = "Barter";
	break;
case "2":
	$output = "Bikes";
	break;
case "3":
	$output = "Cars/Trucks/Motorcycles";
	break;
case "4":
	$output = "Books";
	break;
case "5":
	$output = "CD/DVD/VHS";
	break;
case "6":
	$output = "Free";
	break;
case "7":
	$output = "Clothing & Accessories";
	break;
case "8":
	$output = "Furniture";
	break;
case "9":
	$output = "General";
	break;
case "10":
	$output = "Computer";
	break;
case "11":
	$output = "Jewelry";
	break;
case "12":
	$output = "Electronics";
	break;
case "13":
	$output = "Sporting";
	break;
case "14":
	$output = "Household";
	break;
case "15":
	$output = "Tools";
	break;
case "16":
	$output = "Musical Instruments";
	break;
case "17":
	$output = "Wanted";
	break;
case "18":
	$output = "Accounting/Finance";
	break;
case "19":
	$output = "Administrative/Office";
	break;
case "20":
	$output = "Art/Design";
	break;
case "21":
	$output = "Buisness/Management";
	break;
case "22":
	$output = "Education";
	break;
case "23":
	$output = "Government";
	break;
case "24":
	$output = "Medical/Health";
	break;
case "25":
	$output = "Non-Profit";
	break;
case "26":
	$output = "Retail/Food/Hospitality";
	break;
case "27":
	$output = "Sales/Customer Service";
	break;
case "28":
	$output = "Skilled Trade/Craft";
	break;
case "29":
	$output = "IT/Web Design";
	break;
case "30":
	$output = "TV/Film/Video";
	break;
case "31":
	$output = "Writing/Editing";
	break;
case "32":
	$output = "Other";
	break;
case "33":
	$output = "Lost & Found";
	break;
case "34":
	$output = "Rideshare";
	break;
case "35":
	$output = "Pets";
	break;
case "36":
	$output = "Volunteers";
	break;
case "37":
	$output = "Events";
	break;
case "38":
	$output = "Apartments/Housing";
	break;
case "39":
	$output = "Rooms/Shared";
	break;
case "40":
	$output = "Sublets/Temporary";
	break;
case "41":
	$output = "Housing Wanted";
	break;
case "42":
	$output = "Automotive";
	break;
case "43":
	$output = "Computer";
	break;
case "44":
	$output = "Creative";
	break;
case "45":
	$output = "Skilled Trade/Craft";
	break;
case "46":
	$output = "Financial";
	break;
case "47":
	$output = "Lessons";
	break;
case "48":
	$output = "Musicians";
	break;
}
echo $output;
}
?>

[artacus]

The NEW  method is to use an AJAX call to populate the second box after a selection has been made in the first. The OLD method used javascript arrays to make the appropriate adjustments. I'd strongly recommend the AJAX approach.

[ozfred]

So I am ussing PHP and two while loops to populate two separate drop down menus in my from from information stored in my DB. That works no problem. However I want to be able to change which options are desplayed in the second menu based on what is selected in the first. I have definately seen this done on websites before.  Anyways, can someone point me in a direction for me to start figuring this out, my JavaScript for dummies book isnt helping me.

 

 

This should get you going:

 

  <url: http://www.javascripttoolbox.com/lib/dynamicoptionlist/ >

 

Or search comp.lang.javascript for 'dynamic option list', a link is in my signature.

[fenway]

The NEW  method is to use an AJAX call to populate the second box after a selection has been made in the first. The OLD method used javascript arrays to make the appropriate adjustments. I'd strongly recommend the AJAX approach.

Unless it's a small static list, and there's no need to go back to the server constantly.

[bluebyyou]

Basically...its a classified page... with 5 main categories. and about 40 subcategories.

so I have two tables in my DB. So my first dropdown box uses a while loop to grab the 5 main categories.   my sub category table has three fields the subcategorynumber(primary key), its corresponding main category, and the sub category name. When a user selects a main category I want the sub category box to display only those that correspond to the main category selected....I read over this and its a long explanation about what you probably already get. But I want to set it up like this so when I have an admin page, I can add categories and sub categories but just updating the database. So heres the page im working on...http://www.rockypages.com/insert.php

[fenway]

Well, the admin side of things is totally different...