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+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>
+    CSS Values and Units Test:
+    Attributes references (pixels)
+  </title>
+  <meta name="assert" content="
+    When the value of the referenced attribute is not a pixel value, the fallback value is used instead.
+  " />
+
+  <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; }
+
+      #outer { width: attr(data-test px, 200px); height: 200px; }
+
+  </style>
+
+</head>
+<body>
+
+  <div id="outer" data-test="300px"></div>
+
+</body>
+</html>