Don't clear readonly text fields when set

spec/driver_spec.rb

@@ -773,6 +773,7 @@ describe Capybara::Webkit::Driver do
             <input type="text" name="foo" value="bar"/>
             <input type="text" name="maxlength_foo" value="bar" maxlength="10"/>
             <input type="text" id="disabled_input" disabled="disabled"/>
+            <input type="text" id="readonly_input" readonly="readonly" value="readonly"/>
             <input type="checkbox" name="checkedbox" value="1" checked="checked"/>
             <input type="checkbox" name="uncheckedbox" value="2"/>
             <select name="animal">
@@ -981,6 +982,12 @@ describe Capybara::Webkit::Driver do
     it "knows a not disabled input is not disabled" do
       enabled_input['disabled'].should_not be_true
     end
+
+    it "does not modify a readonly input" do
+      readonly_input = driver.find_css("#readonly_input").first
+      readonly_input.set('enabled')
+      readonly_input.value.should == 'readonly'
+    end
   end
 
   context "dom events" do

spec/selenium_compatibility_spec.rb

@@ -9,6 +9,7 @@ describe Capybara::Webkit, 'compatibility with selenium' do
         <form onsubmit="return false">
           <label for="one">One</label><input type="text" name="one" id="one" />
           <label for="two">Two</label><input type="text" name="two" id="two" />
+          <label for="three">Three</label><input type="text" name="three" id="three" readonly="readonly" />
           <input type="submit" value="Submit" id="submit" />
         </form>
         <script type="text/javascript">
@@ -33,6 +34,7 @@ describe Capybara::Webkit, 'compatibility with selenium' do
       fill_in "One", :with => "some value"
       fill_in "One", :with => "a new value"
       fill_in "Two", :with => "other value"
+      fill_in "Three", :with => "readonly value"
       click_button "Submit"
     end
   end

src/capybara.js

@@ -242,7 +242,9 @@ Capybara = {
         length = value.length;
       }
 
-      node.value = "";
+      if (!node.readOnly)
+        node.value = "";
+
       for (strindex = 0; strindex < length; strindex++) {
         CapybaraInvocation.keypress(value[strindex]);
       }