diff --git a/examples/demos/TicTacToe/TicTacToe.js b/examples/demos/TicTacToe/TicTacToe.js
index 860d5c53..386284f0 100644
--- a/examples/demos/TicTacToe/TicTacToe.js
+++ b/examples/demos/TicTacToe/TicTacToe.js
@@ -113,7 +113,7 @@ var Cell = React.createClass({
       case 2:
         return styles.cellTextO;
       default:
-        return {};
+        return null;
     }
   },
 
diff --git a/src/apis/AppRegistry/__tests__/__snapshots__/renderApplication-test.js.snap b/src/apis/AppRegistry/__tests__/__snapshots__/renderApplication-test.js.snap
index 1ac43ffb..a428fed8 100644
--- a/src/apis/AppRegistry/__tests__/__snapshots__/renderApplication-test.js.snap
+++ b/src/apis/AppRegistry/__tests__/__snapshots__/renderApplication-test.js.snap
@@ -7,7 +7,7 @@ button::-moz-focus-inner,input::-moz-focus-inner{border:0;padding:0}
 input::-webkit-inner-spin-button,input::-webkit-outer-spin-button,input::-webkit-search-cancel-button,input::-webkit-search-decoration,input::-webkit-search-results-button,input::-webkit-search-results-decoration{display:none}
 @keyframes rn-ActivityIndicator-animation{0%{-webkit-transform: rotate(0deg); transform: rotate(0deg);}100%{-webkit-transform: rotate(360deg); transform: rotate(360deg);}}
 @keyframes rn-ProgressBar-animation{0%{-webkit-transform: translateX(-100%); transform: translateX(-100%);}100%{-webkit-transform: translateX(400%); transform: translateX(400%);}}
-.rn_pointerEvents\\:auto,.rn_pointerEvents\\:box-only,.rn_pointerEvents\\:box-none *{pointer-events:auto}.rn_pointerEvents\\:none,.rn_pointerEvents\\:box-only *,.rn_pointerEvents\\:box-none{pointer-events:none}
+.rn-pointerEvents\\:auto,.rn_pointerEvents\\:box-only,.rn-pointerEvents\\:box-none *{pointer-events:auto}.rn-pointerEvents\\:none,.rn_pointerEvents\\:box-only *,.rn-pointerEvents\\:box-none{pointer-events:none}
 .rn-bottom\\:0px{bottom:0px}
 .rn-left\\:0px{left:0px}
 .rn-position\\:absolute{position:absolute}
diff --git a/src/apis/StyleSheet/__tests__/__snapshots__/registry-test.js.snap b/src/apis/StyleSheet/__tests__/__snapshots__/registry-test.js.snap
index db8ffeff..75f4e716 100644
--- a/src/apis/StyleSheet/__tests__/__snapshots__/registry-test.js.snap
+++ b/src/apis/StyleSheet/__tests__/__snapshots__/registry-test.js.snap
@@ -1,4 +1,4 @@
-exports[`apis/StyleSheet/registry resolve with stylesheet, resolves to className 1`] = `
+exports[`apis/StyleSheet/registry resolve with register, resolves to className 1`] = `
 Object {
   "className": "
 rn-borderTopColor:red
@@ -17,7 +17,7 @@ rn-width:100px",
 }
 `;
 
-exports[`apis/StyleSheet/registry resolve with stylesheet, resolves to className 2`] = `
+exports[`apis/StyleSheet/registry resolve with register, resolves to className 2`] = `
 Object {
   "className": "
 rn-borderTopColor:red
@@ -36,7 +36,7 @@ rn-width:200px",
 }
 `;
 
-exports[`apis/StyleSheet/registry resolve with stylesheet, resolves to className 3`] = `
+exports[`apis/StyleSheet/registry resolve with register, resolves to className 3`] = `
 Object {
   "className": "
 rn-borderTopColor:red
@@ -55,7 +55,7 @@ rn-width:100px",
 }
 `;
 
-exports[`apis/StyleSheet/registry resolve with stylesheet, resolves to mixed 1`] = `
+exports[`apis/StyleSheet/registry resolve with register, resolves to mixed 1`] = `
 Object {
   "className": "
 rn-left:50px
@@ -75,7 +75,7 @@ rn-position:absolute",
 }
 `;
 
-exports[`apis/StyleSheet/registry resolve with stylesheet, resolves to mixed 2`] = `
+exports[`apis/StyleSheet/registry resolve with register, resolves to mixed 2`] = `
 Object {
   "className": "
 rn-left:50px
@@ -95,7 +95,7 @@ rn-width:200px",
 }
 `;
 
-exports[`apis/StyleSheet/registry resolve with stylesheet, resolves to mixed 3`] = `
+exports[`apis/StyleSheet/registry resolve with register, resolves to mixed 3`] = `
 Object {
   "className": "
 rn-left:50px
@@ -115,7 +115,7 @@ rn-position:absolute",
 }
 `;
 
-exports[`apis/StyleSheet/registry resolve without stylesheet, resolves to inline styles 1`] = `
+exports[`apis/StyleSheet/registry resolve without register, resolves to inline styles 1`] = `
 Object {
   "className": "
 ",
@@ -136,7 +136,7 @@ Object {
 }
 `;
 
-exports[`apis/StyleSheet/registry resolve without stylesheet, resolves to inline styles 2`] = `
+exports[`apis/StyleSheet/registry resolve without register, resolves to inline styles 2`] = `
 Object {
   "className": "
 ",
@@ -157,7 +157,7 @@ Object {
 }
 `;
 
-exports[`apis/StyleSheet/registry resolve without stylesheet, resolves to inline styles 3`] = `
+exports[`apis/StyleSheet/registry resolve without register, resolves to inline styles 3`] = `
 Object {
   "className": "
 ",
diff --git a/src/apis/StyleSheet/__tests__/injector.js b/src/apis/StyleSheet/__tests__/injector.js
index 72cdbe01..0e50932f 100644
--- a/src/apis/StyleSheet/__tests__/injector.js
+++ b/src/apis/StyleSheet/__tests__/injector.js
@@ -2,7 +2,7 @@
 
 import injector from '../injector';
 
-describe('apis/StyleSheet', () => {
+describe('apis/StyleSheet/injector', () => {
   beforeEach(() => {
     document.head.insertAdjacentHTML('afterbegin', `
       <style id="react-native-stylesheet">
@@ -13,10 +13,10 @@ describe('apis/StyleSheet', () => {
   });
 
   test('hydrates from SSR', () => {
-    const classList = injector.getAvailableClassNames();
-    expect(classList).toEqual([
-      'rn-alignItems\\:stretch',
-      'rn-position\\:top'
-    ]);
+    const classList = injector.getClassNames();
+    expect(classList).toEqual({
+      'rn-alignItems\\:stretch': true,
+      'rn-position\\:top': true
+    });
   });
 });
diff --git a/src/apis/StyleSheet/__tests__/prefixeInlineStyles-test.js b/src/apis/StyleSheet/__tests__/prefixInlineStyles-test.js
similarity index 100%
rename from src/apis/StyleSheet/__tests__/prefixeInlineStyles-test.js
rename to src/apis/StyleSheet/__tests__/prefixInlineStyles-test.js
diff --git a/src/apis/StyleSheet/__tests__/registry-test.js b/src/apis/StyleSheet/__tests__/registry-test.js
index e89f29f6..f63edc61 100644
--- a/src/apis/StyleSheet/__tests__/registry-test.js
+++ b/src/apis/StyleSheet/__tests__/registry-test.js
@@ -33,21 +33,21 @@ describe('apis/StyleSheet/registry', () => {
       expect(resolve3).not.toEqual(resolve4);
     };
 
-    test('with stylesheet, resolves to className', () => {
+    test('with register, resolves to className', () => {
       const a = StyleRegistry.register(styleA);
       const b = StyleRegistry.register(styleB);
       const c = StyleRegistry.register(styleC);
       testResolve(a, b, c);
     });
 
-    test('with stylesheet, resolves to mixed', () => {
+    test('with register, resolves to mixed', () => {
       const a = styleA;
       const b = StyleRegistry.register(styleB);
       const c = StyleRegistry.register(styleC);
       testResolve(a, b, c);
     });
 
-    test('without stylesheet, resolves to inline styles', () => {
+    test('without register, resolves to inline styles', () => {
       testResolve(styleA, styleB, styleC);
     });
   });
diff --git a/src/apis/StyleSheet/initialize.js b/src/apis/StyleSheet/initialize.js
index 975a6811..f98d3453 100644
--- a/src/apis/StyleSheet/initialize.js
+++ b/src/apis/StyleSheet/initialize.js
@@ -28,11 +28,12 @@ const initialize = () => {
   );
   injector.addRule(
     'pointer-events',
-    '.rn_pointerEvents\\:auto,.rn_pointerEvents\\:box-only,.rn_pointerEvents\\:box-none *{pointer-events:auto}' +
-    '.rn_pointerEvents\\:none,.rn_pointerEvents\\:box-only *,.rn_pointerEvents\\:box-none{pointer-events:none}'
+    '.rn-pointerEvents\\:auto,.rn_pointerEvents\\:box-only,.rn-pointerEvents\\:box-none *{pointer-events:auto}' +
+    '.rn-pointerEvents\\:none,.rn_pointerEvents\\:box-only *,.rn-pointerEvents\\:box-none{pointer-events:none}'
   );
 
-  StyleRegistry.initialize();
+  const classNames = injector.getClassNames();
+  StyleRegistry.initialize(classNames);
 };
 
 export default initialize;
diff --git a/src/apis/StyleSheet/injector.js b/src/apis/StyleSheet/injector.js
index 74a66bb5..1eccd631 100644
--- a/src/apis/StyleSheet/injector.js
+++ b/src/apis/StyleSheet/injector.js
@@ -5,14 +5,31 @@
 
 import asap from 'asap';
 
+const emptyObject = {};
 const hasOwnProperty = Object.prototype.hasOwnProperty;
 
 const CLASSNAME_REXEP = /\.rn-([^{;\s]+)/g;
 const STYLE_ELEMENT_ID = 'react-native-stylesheet';
+
 let registry = {};
 let isDirty = false;
-let styleNode = null;
 
+/**
+ * Registers a rule and requests an update to the style sheet
+ */
+const addRule = (key, rule) => {
+  if (!registry[key]) {
+    registry[key] = rule;
+    isDirty = true;
+    if (global.document) {
+      asap(frame);
+    }
+  }
+};
+
+/**
+ * Returns a string of the registered rules
+ */
 const getStyleText = () => {
   /* eslint prefer-template:0 */
   let result = '\n';
@@ -24,66 +41,66 @@ const getStyleText = () => {
   return result;
 };
 
-// TODO: SSR support
-const getAvailableClassNames = () => {
+/**
+ * Returns an HTML string for server rendering
+ */
+const getStyleSheetHtml = () => `<style id="${STYLE_ELEMENT_ID}">${getStyleText()}</style>`;
+
+const reset = () => { registry = {}; };
+
+/**
+ * Finds or injects the style sheet when in a browser environment
+ */
+let styleNode = null;
+const getStyleNode = () => {
   if (global.document) {
     if (!styleNode) {
+      // look for existing style sheet (could also be server-rendered)
       styleNode = document.getElementById(STYLE_ELEMENT_ID);
+      if (!styleNode) {
+        // if there is no existing stylesheet, inject it style sheet
+        document.head.insertAdjacentHTML('afterbegin', getStyleSheetHtml());
+        styleNode = document.getElementById(STYLE_ELEMENT_ID);
+      }
     }
-    if (styleNode) {
-      const text = styleNode.textContent;
-      return text.match(CLASSNAME_REXEP).map((name) => name.slice(1));
-    } else {
-      return [];
-    }
-  } else {
-    return [];
+    return styleNode;
   }
 };
 
-const createStyleHTML = (text) => `<style id="${STYLE_ELEMENT_ID}">${text}</style>`;
+/**
+ * Determines which classes are available in the existing document. Doesn't
+ * rely on the registry so it can be used to read class names from a SSR style
+ * sheet.
+ */
+const getClassNames = () => {
+  const styleNode = getStyleNode();
+  if (styleNode) {
+    const text = styleNode.textContent;
+    const matches = text.match(CLASSNAME_REXEP);
+    if (matches) {
+      return matches.map((name) => name.slice(1)).reduce((classMap, className) => {
+        classMap[className] = true;
+        return classMap;
+      }, {});
+    }
+  }
+  return emptyObject;
+};
 
 const frame = () => {
   if (!isDirty || !global.document) { return; }
   isDirty = false;
-  styleNode = styleNode || document.getElementById(STYLE_ELEMENT_ID);
 
-  if (!styleNode) {
-    document.head.insertAdjacentHTML('afterbegin', createStyleHTML());
-    styleNode = document.getElementById(STYLE_ELEMENT_ID);
-  }
-
-  const css = getStyleText();
-
-  if (styleNode.styleSheet) {
-    styleNode.styleSheet.cssText = css;
-  } else {
-    /* eslint no-cond-assign:0 */
-    let last;
-    while (last = styleNode.lastChild) {
-      styleNode.removeChild(last);
-    }
-    styleNode.appendChild(document.createTextNode(css));
+  const styleNode = getStyleNode();
+  if (styleNode) {
+    const css = getStyleText();
+    styleNode.textContent = css;
   }
 };
 
-const addRule = (key, rule) => {
-  if (!registry[key]) {
-    registry[key] = rule;
-    if (!isDirty) {
-      isDirty = true;
-      if (global.document) {
-        asap(frame);
-      }
-    }
-  }
-};
-
-const getStyleSheetHtml = () => createStyleHTML(getStyleText());
-
 module.exports = {
   addRule,
-  getAvailableClassNames,
+  getClassNames,
   getStyleSheetHtml,
-  reset: () => { registry = {}; }
+  reset
 };
diff --git a/src/apis/StyleSheet/registry.js b/src/apis/StyleSheet/registry.js
index 8468b658..28cef65f 100644
--- a/src/apis/StyleSheet/registry.js
+++ b/src/apis/StyleSheet/registry.js
@@ -67,7 +67,6 @@ const registerStyle = (id, flatStyle) => {
  */
 const resolveProps = (reactNativeStyle) => {
   const flatStyle = flattenStyle(reactNativeStyle);
-
   const domStyle = createReactDOMStyle(flatStyle);
   const style = {};
 
@@ -122,9 +121,8 @@ const resolvePropsIfNeeded = (key, style) => {
  * Web style registry
  */
 const StyleRegistry = {
-  initialize() {
-    const classNames = injector.getAvailableClassNames();
-    classNames.forEach((className) => { injectedClassNames[className] = true; });
+  initialize(classNames) {
+    injectedClassNames = classNames;
   },
 
   reset() {