Fixed for Capybara 1.1

Gemfile.lock

@@ -1,24 +1,24 @@
 GEM
   remote: http://rubygems.org/
   specs:
-    capybara (1.0.0)
+    capybara (1.1.1)
       mime-types (>= 1.16)
       nokogiri (>= 1.3.3)
       rack (>= 1.0.0)
       rack-test (>= 0.5.4)
-      selenium-webdriver (~> 0.2.0)
+      selenium-webdriver (~> 2.0)
       xpath (~> 0.1.4)
-    childprocess (0.1.9)
+    childprocess (0.2.2)
       ffi (~> 1.0.6)
     diff-lcs (1.1.2)
     ffi (1.0.9)
-    json_pure (1.5.3)
+    json_pure (1.6.0)
     mime-types (1.16)
     mini_magick (3.2.1)
       subexec (~> 0.0.4)
     nokogiri (1.5.0)
-    rack (1.3.0)
-    rack-test (0.6.0)
+    rack (1.3.2)
+    rack-test (0.6.1)
       rack (>= 1.0)
     rake (0.9.2)
     rspec (2.6.0)
@@ -30,8 +30,8 @@ GEM
       diff-lcs (~> 1.1.2)
     rspec-mocks (2.6.0)
     rubyzip (0.9.4)
-    selenium-webdriver (0.2.2)
-      childprocess (>= 0.1.9)
+    selenium-webdriver (2.6.0)
+      childprocess (>= 0.2.1)
       ffi (>= 1.0.7)
       json_pure
       rubyzip

lib/capybara/driver/webkit.rb

@@ -10,6 +10,9 @@ class WebkitInvalidResponseError < StandardError
   class WebkitNoResponseError < StandardError
   end
 
+  class NodeNotAttachedError < Capybara::ElementNotFound
+  end
+
   attr_reader :browser
 
   def initialize(app, options={})

lib/capybara/driver/webkit/node.rb

@@ -88,7 +88,15 @@ def find(xpath)
     end
 
     def invoke(name, *args)
-      browser.command "Node", name, native, *args
+      if attached?
+        browser.command "Node", name, native, *args
+      else
+        raise Capybara::Driver::Webkit::NodeNotAttachedError
+      end
+    end
+
+    def attached?
+      browser.command("Node", "isAttached", native) == "true"
     end
 
     def browser

src/capybara.js

@@ -27,6 +27,10 @@ Capybara = {
     return results.join(",");
   },
 
+  isAttached: function(index) {
+    return document.evaluate("ancestor-or-self::html", this.nodes[index], null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue != null;
+  },
+
   text: function (index) {
     var node = this.nodes[index];
     var type = (node.type || node.tagName).toLowerCase();