diff --git a/lib/patch/jsdom.js b/lib/patch/jsdom.js
index f22bc4a5..add83bd7 100644
--- a/lib/patch/jsdom.js
+++ b/lib/patch/jsdom.js
@@ -170,6 +170,113 @@ var WIDTH = (function () {
 })();
 
 
+//
+//  Patch for CSSStyleDeclaration lengthRegEx so that it includes ex units
+//  (plus a number of other units that are left out)
+//  
+var FixValueType = function () {
+  var parsers = require(PARSERS);
+  
+  var integerRegEx = /^[\-+]?[0-9]+$/;
+  var numberRegEx = /^[\-+]?[0-9]*\.[0-9]+$/;
+  var lengthRegEx = /^(0|[\-+]?[0-9]*\.?[0-9]+(in|cm|mm|pt|pc|px|em|ex|ch|rem|vh|vw|vmin|vmax))$/;
+  var percentRegEx = /^[\-+]?[0-9]*\.?[0-9]+%$/;
+  var urlRegEx = /^url\(\s*([^\)]*)\s*\)$/;
+  var stringRegEx = /^(\"[^\"]*\"|\'[^\']*\')$/;
+  var colorRegEx1 = /^#[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]([0-9a-fA-F][0-9a-fA-F][0-9a-fA-F])?$/;
+  var colorRegEx2 = /^rgb\(([^\)]*)\)$/;
+  var colorRegEx3 = /^rgba\(([^\)]*)\)$/;
+  var angleRegEx = /^([\-+]?[0-9]*\.?[0-9]+)(deg|grad|rad)$/;
+
+  parsers.valueType = function valueType(val) {
+    var TYPES = parsers.TYPES;
+    if (val === '' || val === null) return TYPES.NULL_OR_EMPTY_STR;
+    if (typeof val === 'number') val = val.toString();
+    if (typeof val !== 'string') return undefined;
+
+    if (integerRegEx.test(val)) return TYPES.INTEGER;
+    if (numberRegEx.test(val))  return TYPES.NUMBER;
+    if (lengthRegEx.test(val))  return TYPES.LENGTH;
+    if (percentRegEx.test(val)) return TYPES.PERCENT;
+    if (urlRegEx.test(val))     return TYPES.URL;
+    if (stringRegEx.test(val))  return TYPES.STRING;
+    if (angleRegEx.test(val))   return TYPES.ANGLE;
+    if (colorRegEx1.test(val))  return TYPES.COLOR;
+    var res = colorRegEx2.exec(val);
+    var parts;
+    if (res !== null) {
+      parts = res[1].split(/\s*,\s*/);
+      if (parts.length !== 3) return undefined;
+      if (parts.every(percentRegEx.test.bind(percentRegEx)) ||
+          parts.every(integerRegEx.test.bind(integerRegEx))) return TYPES.COLOR;
+      return undefined;
+    }
+    res = colorRegEx3.exec(val);
+    if (res !== null) {
+      parts = res[1].split(/\s*,\s*/);
+      if (parts.length !== 4) return undefined;
+      if (parts.slice(0, 3).every(percentRegEx.test.bind(percentRegEx)) ||
+          parts.every(integerRegEx.test.bind(integerRegEx))) {
+        if (numberRegEx.test(parts[3])) return TYPES.COLOR;
+      }
+      return undefined;
+    }
+    val = val.toLowerCase();
+    switch (val) {
+     case 'maroon':
+     case 'red':
+     case 'orange':
+     case 'yellow':
+     case 'olive':
+     case 'purple':
+     case 'fuchsia':
+     case 'white':
+     case 'lime':
+     case 'green':
+     case 'navy':
+     case 'blue':
+     case 'aqua':
+     case 'teal':
+     case 'black':
+     case 'silver':
+     case 'gray':
+      // the following are deprecated in CSS3
+     case 'activeborder':
+     case 'activecaption':
+     case 'appworkspace':
+     case 'background':
+     case 'buttonface':
+     case 'buttonhighlight':
+     case 'buttonshadow':
+     case 'buttontext':
+     case 'captiontext':
+     case 'graytext':
+     case 'highlight':
+     case 'highlighttext':
+     case 'inactiveborder':
+     case 'inactivecaption':
+     case 'inactivecaptiontext':
+     case 'infobackground':
+     case 'infotext':
+     case 'menu':
+     case 'menutext':
+     case 'scrollbar':
+     case 'threeddarkshadow':
+     case 'threedface':
+     case 'threedhighlight':
+     case 'threedlightshadow':
+     case 'threedshadow':
+     case 'window':
+     case 'windowframe':
+     case 'windowtext':
+      return TYPES.COLOR;
+     default:
+      return TYPES.KEYWORD;
+    }
+  };
+}
+
+
 //
 //  Patch jsdom functions
 //
@@ -276,4 +383,6 @@ exports.patch = function (jsdom) {
     var core = require("jsdom/lib/jsdom/level1/core");
     Object.defineProperties(core.CSSStyleDeclaration.prototype,{width: WIDTH});
   }
+  div.style.marginTop = "3ex";
+  if (div.style.marginTop !== "3ex") FixValueType();
 }