July 2007

Tip: Passing a shopping cart to Paypal Website Payments Standard

Here's a little tip for anyone using Paypal's Website Payments Standard system for electronic payments on their shopping cart. Their API allows you to pass in a complete shopping cart using a series of form fields listing the items, quantities, etc, as you'd expect. There's one tiny little detail that isn't explicitly stated - the button that you use to submit to the API must not have a name attribute otherwise it will fail. Here's a fully working example to better explain:


SPF the easy way

Sender Policy Framework (SPF) is an open standard that aims to help prevent spam, and stop legitimate email from being tagged as such. While the specifications can take some time to understand, there are some web-based tools to help you make creating your SPF records a little easier than by hand, but I still find them to be a bit misleading. According to the SPF FAQ the simplest way to create your SPF record is to simply list the IP addresses of all servers that mail goes out through, e.g.:


Scriptaculous + JS optimizations can cause problems

With everyone raving about YSlow I used it to prune a new project I was doing. Well, after the results worked just great with Safari and Firefox I was thoroughly confused why it wasn't working correctly in IE. The problem was that my Script.aculo.us routines weren't working, and more specifically I was getting really weird errors when the page was loading, before any of the routines executed. Some of the errors were very vague, e.g. "'Class' is undefined", and "Effect.toggle is undefined".