What's it good for? When you try to validate an XHTML document containing hyperlinks having the attribute target (needed usually for target="_blank" hyperlinks), validation fails with the error message there is no attribute "target". Well meant, but useless hint is: this is usually fixed by using CSS to achieve the desired effect instead. System Plugin Target Blank XHTML Complier can help: You just make links including target="_blank" links as you wish and be used to - most WYSIWYG editors and menu modules would do so anyway. Once the plugin is activated, the document validates nicely (at least no there is no attribute "target" anymore), but the links keep opening new windows as desired. Really? Do they? Well the browser or outputting device must support windows (in order to open a new one), and javascript. No added value for screenreaders. How does it work? It a) replaces all occurrences of target="_blank" with rel="extern", and b) inserts a javascript which adds target="_blank" attribute to all links having rel="extern" attribute in page load event, which gives the functionality back to the links. Demo Go to http://din18040.de and hit the W3C validator button: It opens a new window (target _blank), but still vaidates as XHTML (no target _blank in Source of page).