diff --git a/CHANGELOG b/CHANGELOG
index 59f5020..43db9e1 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Add Prototype.Browser.MobileSafari which evaluates to true on the iPhone's browser.  [sam]
+
 * Optimize Selector#match and Element#match for simple selectors.  Closes #9082.  [Andrew Dupont]
 
 * Remove the dependency on Element.ClassNames from Element#addClassName/removeClassName/toggleClassName, and deprecate Element.ClassNames. Closes #9073. [Tobie Langel]
diff --git a/src/prototype.js b/src/prototype.js
index 9ff3816..e65893c 100644
--- a/src/prototype.js
+++ b/src/prototype.js
@@ -7,16 +7,16 @@ var Prototype = {
     IE:     !!(window.attachEvent && !window.opera),
     Opera:  !!window.opera,
     WebKit: navigator.userAgent.indexOf('AppleWebKit/') > -1,
-    Gecko:  navigator.userAgent.indexOf('Gecko') > -1 && navigator.userAgent.indexOf('KHTML') == -1
+    Gecko:  navigator.userAgent.indexOf('Gecko') > -1 && navigator.userAgent.indexOf('KHTML') == -1,
+    MobileSafari: !!navigator.userAgent.match(/iPhone.*Mobile.*Safari/)
   },
 
   BrowserFeatures: {
     XPath: !!document.evaluate,
     ElementExtensions: !!window.HTMLElement,
     SpecificElementExtensions: 
-      navigator.userAgent.indexOf('iPhone') == -1 &&
-      (document.createElement('div').__proto__ !== 
-       document.createElement('form').__proto__)
+      document.createElement('div').__proto__ !== 
+       document.createElement('form').__proto__
   },
 
   ScriptFragment: '<script[^>]*>([\\S\\s]*?)<\/script>',
@@ -24,7 +24,10 @@ var Prototype = {
   
   emptyFunction: function() { },
   K: function(x) { return x }
-}
+};
+
+if (Prototype.Browser.MobileSafari)
+  Prototype.BrowserFeatures.SpecificElementExtensions = false;
 
 <%= include 'base.js', 'string.js' %>