Address comments

IPython/html/tests/notebook/dualmode.js

@@ -17,7 +17,7 b' casper.notebook_test(function () {'
     this.then(function () {
         if (this.slimerjs) {
             // When running in xvfb, the Slimer window doesn't always have focus
-            // immediately.  By clicking on a new element on the page we ccan force
+            // immediately.  By clicking on a new element on the page we can force
             // it to gain focus.
             this.click_cell_editor(1);
             this.click_cell_editor(0);

IPython/html/tests/util.js

@@ -464,7 +464,7 b' casper.notebook_test = function(test) {'
     }
     
     // Make sure to remove the onbeforeunload callback.  This callback is 
-    // responsable for the "Are you sure you want to quit?" type messages.
+    // responsible for the "Are you sure you want to quit?" type messages.
     // PhantomJS ignores these prompts, SlimerJS does not which causes hangs.
     this.then(function(){
         this.evaluate(function(){

IPython/testing/iptestcontroller.py

@@ -257,12 +257,10 b' class JSController(TestController):'
     def wait(self, *pargs, **kwargs):
         """Wait for the JSController to finish"""
         ret = super(JSController, self).wait(*pargs, **kwargs)
-        # If this is a SlimerJS controller, echo the captured output.
+        # If this is a SlimerJS controller, check the captured stdout for
+        # errors.  Otherwise, just return the return code.
         if self.engine == 'slimerjs':
-            # Echo captured output.
             stdout = bytes_to_str(self.stdout)
-            print(stdout)
-            # Return True if a failure occured.
             return self.slimer_failure.search(strip_ansi(stdout))
         else:
             return ret
@@ -376,7 +374,7 b' def prepare_controllers(options):'
         else:
             js_testgroups = all_js_groups()
 
-    engine = 'phantomjs' if have['phantomjs'] and not options.slimerjs else 'slimerjs'
+    engine = 'slimerjs' if options.slimerjs else 'phantomjs'
     c_js = [JSController(name, engine=engine) for name in js_testgroups]
     c_py = [PyTestController(name, options) for name in py_testgroups]