Attention 4chan extension/user script/archive developers: Some time in the next few days, we'll be rolling out a complete HTML rewrite of the imageboards. The design will remain the same, but the underlying HTML/CSS is completely new, and validates HTML5/CSS3 (with some tweaks to account for cross-browser compatibility).
Please visit this thread to read more about the changes, and here to preview the code.
As a regular user, these changes should not affect you. You will need to update your 4chan browser extensions/user scripts when their maintainer updates them to be compatible with the changes. The official 4chan Chrome extension will be ready to go when the updates happen, and 4chan X should be ready soon. We'll post more details on the day of the migration!