It took me a while to track down why I was getting javascript errors with a onchange event. The error said that the object didn't support the method or propert.
Here's an example of the problem
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<title>New Page </title>
</head>
<body>
<form method="post" action="<? echo $PHP_SELF; ?>" name="books">
<TABLE>
<tr>
<td width="80%" colspan="2"><div align="right"><p class="BOLD">Choose your country:</td>
<td width="20%" valign="middle" align="center">
<select name="shipcountry" onchange="document.books.submit()" size="1">
<option value="United States" SELECTED >United States</option>
<option value="Canada/Mexico" >Canada/Mexico</option>
<option value="Elsewhere" >Elsewhere</option>
</select></td>
</tr>
<TR>
<TD>
<input type="submit" value="submit" name="submit">
</TD>
</TR>
<? echo "You said ".$shipcountry; ?>
</TABLE>
</form>
</body>
and the answer is not nameing the submit button "submit". Name it something else. I have looked for other people falling prey to this. Maybe its a browser specific issue? I have only tested it under IE5.0.
Mike