Someone recently sent me an email message concerning a problem they were having with my 
JJW.cc version of the Web store.  The problem involved an "Image Button Bug" which everyone 
should know about.
 
The error/problem was this:
 
The shopping cart was a "super cart" type which used an Image Button for the "Submit Quantity 
Changes".  Sometimes when submitting changes the user would receive a "Bad Change Quantity" 
Error Message --- even though the quantity change numbers were obviously greater than zero!
 
As some of you already realize, browsers will return name/value pairs (into %form_data) for 
the x and y coordinates of where the image button was click on ( x=3, y=0 for example).  
The problem was that the browser was sending coordinate values for x and y which in some 
cases were zero.  This caused the code in sub "modify_quantity_of_items_in_cart" to think 
that there was a change quantity of zero, producing the "Bad Change Quantity" Error Message .
 
This fix is very simple:
 
In web_store.cgi find the subroutine "modify_quantity_of_items_in_cart":
 
Change the IF statement:
 
    if ((($key =~ /[\d]/) && ($form_data{$key} =~ /\D/)) ||
        $form_data{$key} eq "0")
to:
 
    if (($key =~ /[\d]/ && $form_data{$key} =~ /\D/) || 
     ($key =~ /[\d]/ && $form_data{$key} eq "0"))
That's it.