Dependant Drop Down w/ MX Widget and Submit Function

[ams53]

I used DW MX 2004 and the MX Widget Ext. to build a dependant drop down function.  The drop downs work great in filtering the databases down to the specific product.  However, I can't figure out how to link the last drop down to a display/ result page (product specific page).  I've tried using url param and java onClick, but the same page loads every time.

 

This is the type of code I've used.

 

onClick="document.location.href='product.php?product_id=<? php echo [$rowRecordset5('product_id')]; ?>'"

 

Three questions:

 

Where am I going wrong with linking the selection in the last drop down with the results page?

 

Is there a better way to build dependant drop down menus when using a lot of files?  If so, any good books or tutorials to learn from?

 

Thanks for helping this newbie.