<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title> CSS Values and Units Test: Attribute references (length) </title> <meta name="assert" content=" The value of referenced attribute is used correctly as a length (even if it's 0). " /> <link rel="author" title="François REMY" href="mailto:fremycompany.developer@yahoo.fr" / > <link rel="help" href="http://www.w3.org/TR/css3-values/#attr-notation"/> <link rel="match" href="reference/200-200-green.html" /> <style type="text/css"> html, body { margin: 0px; padding: 0px; } html { background: white; overflow: hidden; } #outer { position: relative; background: green; } #outer2 { background: red; } #outer { width: 200px; height: 200px; } #outer2 { width: 200px; width: attr(data-test length, 0); height: 200px; } </style> </head> <body> <div id="outer"></div> <div id="outer2" data-test="0"></div> </body> </html>