Dynamicaly Linked Drop Down Lists

[bam720]

I am working on a project where I have one List that contains the company name, and the second list is the companies location (One Company can have many locations). I want the user to pick the company and then only be able to select the relevant locations. I udnerstand that using php the form needs to submitted, but am unsure of how that works. I've tried using the "this.form.submit()" method which to my understanding is a javascript call. However this call is not doing anything at all. Here is the relevant code:

<form action="eform.php" method="post" name="client">
<p align="left"><strong>Client Information </strong></p>
<p align="left"> Name: 
<?php
	$conn = new COM('ADODB.Connection');  //for MS Access connection
	$conn = odbc_connect('clientinfo','Terminal','');

	echo'<select name="ClientName" onchange=>"this.form.submit()"';
		$sql = 'SELECT * FROM Clients';
		$clookup = odbc_exec($conn,$sql);
  		while (odbc_fetch_row($clookup))
			{
			$PID=odbc_result($clookup,"PrimeID");
			if($PID!=$PrevPID)
   				echo "<option value=\"".$PID."\">".$PID."</option><br>";
			$PrevPID=$PID;
    		}
		echo '</select>';
?>
  </p>
<p align="left">Location: 
<?php
	$conn = new COM('ADODB.Connection');  //for MS Access connection
	$conn = odbc_connect('clientinfo','Terminal','');

	echo'<select name="Location" onchange=>';
		$sql = 'SELECT * FROM Clients WHERE PrimeID = '.$_POST['ClientName'];
		$clookup = odbc_exec($conn,$sql);
  		while (odbc_fetch_row($clookup))
			{
			$Loc=odbc_result($clookup,"SecondID");
			if($PID!=$PrevPID)
   				echo "<option value=\"".$Loc."\">".$Loc."</option><br>";
			$PrevPID=$PID;
    		}
		echo '</select>';
?>
</p>
</form>

Thanks

 

[bam720]

Nevermind It was a simple typo error.

echo'<select name="ClientName" onchange=>"this.form.submit()"';

And having worked in ADA for so long => looks completly valid but should be

echo'<select name="ClientName" onchange="this.form.submit()">';

 

[DRJ478]

This really is a JavaScript question. But, here's an answer:
Change your code to onSubmit="document.client.submit();"
The identifier 'this' refers to the current element, which is a 'select'. You need to refer to the form itself, either using the document.forms[0].submit() [given it is the first form on the page], or get it with DOM [then the form tag needs an id], or by name as shown above.

 

[Vragabond]

DRJ478, the syntax is correct, since according to html DOM all form elements contain an attribute called form which returns form element that contains the current element (this). So, the syntax is correct and will work. More here:

http://www.w3.org/TR/2003/REC-DOM-Level-2-HTML-20030109/html.html#ID-94282980

However, you are right, it is a JS question rather than php one.

 

[DRJ478]

vragabond
Thanks for the point - there's always something to learn.
However, in order to be independent from DOM Level 2 requirements the suggested code should also work.