This is a frontend for Nu Html Checker written with HTML5 / CSS3 / Javascript.
Live demonstration is available at http://validator.befive.info/
Download the repo and decompress. Rename the folder and drag and drop the folder into anywhere in your webserver folder.
Enter urls into the textarea. If you want to bulk validate a Wordpress site, you can use List Urls WordPress plugin and paste the content of CSV into the textarea below. Supported data formats are sitemap XML, html (source), CSV generated by List Urls Wordpress plugin and plain text with url on each line.
To find out how to use this frontend with your local validation server, please check out this blog post.