… so yeah, I now make it a habit of running my code through the validator just in case I missed something. Markup issues seem so easy to fix on the surface, but the validator can help a lot when you have a *lot* of nested tags.

Process note: The default page on the validator shows you an input box where you need to put in a URL, but you can  also validate your code via file upload or “direct input”. That is, if your markup isn’t being hosted at a public URL, you can simply view:source and copy/paste your code into the text box that appears under the “direct input” tab.