Actualización

web/assets/modernizr/feature-detects/css-vwunit.js

@@ -0,0 +1,14 @@
+// https://github.com/Modernizr/Modernizr/issues/572
+// http://jsfiddle.net/FWeinb/etnYC/
+Modernizr.addTest('cssvwunit', function(){
+    var bool;
+    Modernizr.testStyles("#modernizr { width: 50vw; }", function(elem, rule) {
+        var width = parseInt(window.innerWidth/2,10),
+            compStyle = parseInt((window.getComputedStyle ?
+                      getComputedStyle(elem, null) :
+                      elem.currentStyle)["width"],10);
+        
+        bool= (compStyle == width);
+    });
+    return bool;
+});