prototype: Make submitting forms work in Opera < 9.1.

CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Make submitting forms work in Opera < 9.1. Closes #9917, #9463, #8260. [kangax]
+
 * Fix template evaluation with empty replacements.  Closes #9692.  [Ryan McGeary]
 
 * Hash#toTemplateReplacements is an alias for Hash#toObject so you can once again pass hashes to Template#evaluate and String#interpolate.  [sam]

src/prototype.js

@@ -15,6 +15,7 @@ var Prototype = {
     XPath: !!document.evaluate,
     ElementExtensions: !!window.HTMLElement,
     SpecificElementExtensions: 
+      document.createElement('div').__proto__ &&
       document.createElement('div').__proto__ !== 
        document.createElement('form').__proto__
   },