Propagate Javascript errors on page load

Fixes #124. Closes #125.

README.md

@@ -209,6 +209,9 @@ makes debugging easier). Running `rake autocompile` will watch the
 *   Fixed problem with cookies not being clearer between tests on
     PhantomJS 1.7
 
+*   Fixed Javascript errors during page load causes TimeoutErrors.
+    [Issue #124]
+
 ### 0.7.0 ###
 
 #### Features ####

lib/capybara/poltergeist/client/browser.coffee

@@ -35,7 +35,7 @@ class Poltergeist.Browser
 
     if errors.length > 0
       @page.clearErrors()
-      throw new Poltergeist.JavascriptError(errors)
+      @owner.sendError(new Poltergeist.JavascriptError(errors))
     else
       @owner.sendResponse(response)
 

lib/capybara/poltergeist/client/compiled/browser.js

@@ -48,7 +48,7 @@ Poltergeist.Browser = (function() {
     errors = this.page.errors();
     if (errors.length > 0) {
       this.page.clearErrors();
-      throw new Poltergeist.JavascriptError(errors);
+      return this.owner.sendError(new Poltergeist.JavascriptError(errors));
     } else {
       return this.owner.sendResponse(response);
     }

spec/integration/driver_spec.rb

@@ -206,6 +206,10 @@ module Capybara::Poltergeist
         @driver.evaluate_script("1+1").should == 2
       end
 
+      it 'propagates a Javascript error during page load to a ruby exception' do
+        expect { @driver.visit "/poltergeist/js_error" }.to raise_error(JavascriptError)
+      end
+
       it "doesn't propagate a Javascript error to ruby if error raising disabled" do
         driver = Capybara::Poltergeist::Driver.new(nil, :js_errors => false)
         driver.execute_script "setTimeout(function() { omg }, 0)"

spec/support/views/js_error.erb

@@ -0,0 +1,3 @@
+<script type="text/javascript">
+  foo
+</script>