Dynamic Dependent Drop-down selection menus

Hello,

Do you have a tutorial or video that would assist me in attaining this objective?

I know neither Ajax nor Javascript, and so am having a problem.

I have two <Select><Option>.....</Option></Select> menus on a page. The former is for ClassType, the latter for ClassLength.
But unfortunately, the available ClassLengths depend on the ClassTypes.

Therefore, I need the options in the second menu (ClassLength) to change dynamically according as to what is selected in the first (ClassType); and preferably before the Submit button is pushed.

I have tried Googling, and have seen examples where this is done by incorporating both JavaScript and Ajax, but have not spotted anything that is straightforward for me to implement.

Can your tools do this? And if so do you again have either a tutorial or a video? Or even an example I can try to adapt?

I will understand if you do not.

Thank you,
KB

Hi

I THINK I might have found something I can use.

I will report back.
Thank you

Hello,

The Ajax/Javascript is now working perfectly. But it leaves me needing to run your MySQLExecuteQuery extension before the subsequent page loads, and so I can amend the data slightly.

Unfortunately, those execute query instructions give me the following error:

Fatal error: Uncaught Error: Class 'WA_MySQLi_Query' not found in /var/www/vhosts/xxxxxx.com/httpdocs/presenters/presenter_switchboard_classes_view.php:6 Stack trace: #0 {main} thrown in /var/www/vhosts/xxxxx.com/httpdocs/presenters/presenter_switchboard_classes_view.php on line 6

I get that error even when the SQL query string is empty. This is the code involved:

<?php
if ("" === "") {
$ExecuteQuery = new WA_MySQLi_Query($mysqli_xxxxx);
$ExecuteQuery->Statement = "";
$ExecuteQuery->execute();
$ExecuteGoTo = "";
if (function_exists("rel2abs")) $ExecuteGoTo = $ExecuteGoTo?rel2abs($ExecuteGoTo,dirname(__FILE__)):"";
$ExecuteQuery->redirect($ExecuteGoTo);
}
?>

I give you the URL's in the private area, thank you.

Hello,

Your MySQLi extension was placing itself in the wrong location.

The following code snippets had inserted themselves at the tops of the files.

<?php require_once('../Connections/mysqli_xxxxxxxxx.php'); ?>
<?php require_once('../webassist/mysqli/rsobj.php'); ?>
<?php require_once('../webassist/mysqli/authentication.php'); ?>
<?php require_once('../webassist/mysqli/queryobj.php'); ?>

When the extension then came to insert the "ExecuteQuery" code snippet, it was searching ONLY for the upper
rsobj.php
file, and inserted itself there. It therefore pushed
queryobj.php
down the page. It clearly, therefore, did not have the information it needed to execute the instructions upon the database.

As soon as I realized this (fresh morning eyes), I moved the offending queryobj.php line above the ExecuteQuery code snippet, and everything is now working like a dream.

I do not know why it inserted itself into such an inauspicious location, but all is now fixed.

Thank you, and sorry for the inconvenience.
KB.