You can't do that. Though it seems like the sites are composed, they are in fact just embedded viewports (iframe). The only way to scrape username, at the momen

You can't do that. Though it seems like the sites are composed, they are in fact just embedded viewports (iframe). The only way to scrape username, at the moment, is to turn that app into a plugin/bookmarklet, or at least bootstrap from one. EDIT: Or API/embedded script, but that of course requires the cooperation of site's owner.