diff --git a/common/djangoapps/student/views.py b/common/djangoapps/student/views.py
index 645c1249e0..e028f14b7c 100644
--- a/common/djangoapps/student/views.py
+++ b/common/djangoapps/student/views.py
@@ -20,7 +20,7 @@ from django.core.mail import send_mail
 from django.core.urlresolvers import reverse
 from django.core.validators import validate_email, validate_slug, ValidationError
 from django.db import IntegrityError
-from django.http import HttpResponse, HttpResponseRedirect, Http404
+from django.http import HttpResponse, HttpResponseBadRequest, HttpResponseForbidden, HttpResponseNotAllowed, HttpResponseRedirect, Http404
 from django.shortcuts import redirect
 from django_future.csrf import ensure_csrf_cookie, csrf_exempt
 from django.utils.http import cookie_date
@@ -216,14 +216,21 @@ def signin_user(request):
     """
     This view will display the non-modal login form
     """
-    context = {}
+    context = {
+        'course_id': request.GET.get('course_id'),
+        'enrollment_action': request.GET.get('enrollment_action')
+    }
     return render_to_response('login.html', context)
 
+
 def register_user(request):
     """
     This view will display the non-modal registration form
     """
-    context = {}
+    context = {
+        'course_id': request.GET.get('course_id'),
+        'enrollment_action': request.GET.get('enrollment_action')
+    }
     return render_to_response('register.html', context)
 
 
@@ -290,35 +297,47 @@ def try_change_enrollment(request):
     """
     if 'enrollment_action' in request.POST:
         try:
-            enrollment_output = change_enrollment(request)
+            enrollment_response = change_enrollment(request)
             # There isn't really a way to display the results to the user, so we just log it
             # We expect the enrollment to be a success, and will show up on the dashboard anyway
-            log.info("Attempted to automatically enroll after login. Results: {0}".format(enrollment_output))
+            log.info(
+                "Attempted to automatically enroll after login. Response code: {0}; response body: {1}".format(
+                    enrollment_response.status_code,
+                    enrollment_response.content
+                )
+            )
         except Exception, e:
             log.exception("Exception automatically enrolling after login: {0}".format(str(e)))
 
 
-@login_required
-def change_enrollment_view(request):
-    """Delegate to change_enrollment to actually do the work."""
-    return HttpResponse(json.dumps(change_enrollment(request)))
-
-
-
 def change_enrollment(request):
+    """
+    Modify the enrollment status for the logged-in user.
+
+    The request parameter must be a POST request (other methods return 405)
+    that specifies course_id and enrollment_action parameters. If course_id or
+    enrollment_action is not specified, if course_id is not valid, if
+    enrollment_action is something other than "enroll" or "unenroll", if
+    enrollment_action is "enroll" and enrollment is closed for the course, or
+    if enrollment_action is "unenroll" and the user is not enrolled in the
+    course, a 400 error will be returned. If the user is not logged in, 403
+    will be returned; it is important that only this case return 403 so the
+    front end can redirect the user to a registration or login page when this
+    happens. This function should only be called from an AJAX request or
+    as a post-login/registration helper, so the error messages in the responses
+    should never actually be user-visible.
+    """
     if request.method != "POST":
-        raise Http404
+        return HttpResponseNotAllowed(["POST"])
 
     user = request.user
     if not user.is_authenticated():
-        raise Http404
+        return HttpResponseForbidden()
 
-    action = request.POST.get("enrollment_action", "")
-
-    course_id = request.POST.get("course_id", None)
+    action = request.POST.get("enrollment_action")
+    course_id = request.POST.get("course_id")
     if course_id is None:
-        return HttpResponse(json.dumps({'success': False,
-                                        'error': 'There was an error receiving the course id.'}))
+        return HttpResponseBadRequest("Course id not specified")
 
     if action == "enroll":
         # Make sure the course exists
@@ -328,12 +347,10 @@ def change_enrollment(request):
         except ItemNotFoundError:
             log.warning("User {0} tried to enroll in non-existent course {1}"
                       .format(user.username, course_id))
-            return {'success': False, 'error': 'The course requested does not exist.'}
+            return HttpResponseBadRequest("Course id is invalid")
 
         if not has_access(user, course, 'enroll'):
-            return {'success': False,
-                    'error': 'enrollment in {} not allowed at this time'
-                    .format(course.display_name_with_default)}
+            return HttpResponseBadRequest("Enrollment is closed")
 
         org, course_num, run = course_id.split("/")
         statsd.increment("common.student.enrollment",
@@ -347,7 +364,7 @@ def change_enrollment(request):
             # If we've already created this enrollment in a separate transaction,
             # then just continue
             pass
-        return {'success': True}
+        return HttpResponse()
 
     elif action == "unenroll":
         try:
@@ -360,13 +377,11 @@ def change_enrollment(request):
                                   "course:{0}".format(course_num),
                                   "run:{0}".format(run)])
 
-            return {'success': True}
+            return HttpResponse()
         except CourseEnrollment.DoesNotExist:
-            return {'success': False, 'error': 'You are not enrolled for this course.'}
+            return HttpResponseBadRequest("You are not enrolled in this course")
     else:
-        return {'success': False, 'error': 'Invalid enrollment_action.'}
-
-    return {'success': False, 'error': 'We weren\'t able to unenroll you. Please try again.'}
+        return HttpResponseBadRequest("Enrollment action is invalid")
 
 
 @ensure_csrf_cookie
diff --git a/lms/djangoapps/courseware/tests/tests.py b/lms/djangoapps/courseware/tests/tests.py
index 4c9f592797..25a7876a2a 100644
--- a/lms/djangoapps/courseware/tests/tests.py
+++ b/lms/djangoapps/courseware/tests/tests.py
@@ -220,25 +220,20 @@ class LoginEnrollmentTestCase(TestCase):
         # Now make sure that the user is now actually activated
         self.assertTrue(get_user(email).is_active)
 
-    def _enroll(self, course):
-        """Post to the enrollment view, and return the parsed json response"""
+    def try_enroll(self, course):
+        """Try to enroll.  Return bool success instead of asserting it."""
         resp = self.client.post('/change_enrollment', {
             'enrollment_action': 'enroll',
             'course_id': course.id,
         })
-        return parse_json(resp)
-
-    def try_enroll(self, course):
-        """Try to enroll.  Return bool success instead of asserting it."""
-        data = self._enroll(course)
-        print ('Enrollment in %s result: %s'
-               % (course.location.url(), str(data)))
-        return data['success']
+        print ('Enrollment in %s result status code: %s'
+               % (course.location.url(), str(resp.status_code)))
+        return resp.status_code == 200
 
     def enroll(self, course):
         """Enroll the currently logged-in user, and check that it worked."""
-        data = self._enroll(course)
-        self.assertTrue(data['success'])
+        result = self.try_enroll(course)
+        self.assertTrue(result)
 
     def unenroll(self, course):
         """Unenroll the currently logged-in user, and check that it worked."""
@@ -246,8 +241,7 @@ class LoginEnrollmentTestCase(TestCase):
             'enrollment_action': 'unenroll',
             'course_id': course.id,
         })
-        data = parse_json(resp)
-        self.assertTrue(data['success'])
+        self.assertTrue(resp.status_code == 200)
 
     def check_for_get_code(self, code, url):
         """
diff --git a/lms/static/sass/multicourse/_course_about.scss b/lms/static/sass/multicourse/_course_about.scss
index 0982577f42..195760721e 100644
--- a/lms/static/sass/multicourse/_course_about.scss
+++ b/lms/static/sass/multicourse/_course_about.scss
@@ -154,6 +154,15 @@
             @include transition();
             width: flex-grid(5, 8);
           }
+
+          #register_error {
+            background: $error-red;
+            border: 1px solid rgb(202, 17, 17);
+            color: rgb(143, 14, 14);
+            display: none;
+            padding: 12px;
+            margin-top: 5px;
+          }
         }
       }
 
diff --git a/lms/templates/courseware/course_about.html b/lms/templates/courseware/course_about.html
index dc1dc17532..4a1a3e59ca 100644
--- a/lms/templates/courseware/course_about.html
+++ b/lms/templates/courseware/course_about.html
@@ -13,42 +13,26 @@
 
 <%block name="js_extra">
 
-  % if not registered:
-    %if user.is_authenticated():
-      ## If the user is authenticated, clicking the enroll button just submits a form
-      <script type="text/javascript">
-      (function() {
-        $(".register").click(function() {
-          $("#class_enroll_form").submit();
-        });
+  <script type="text/javascript">
+  (function() {
+    $(".register").click(function(event) {
+      $("#class_enroll_form").submit();
+      event.preventDefault();
+    });
 
-        $(document).delegate('#class_enroll_form', 'ajax:success', function(data, json, xhr) {
-          if(json.success) {
-            location.href="${reverse('dashboard')}";
-          }else{
-          $('#register_message').html('<p class="inline-error">' + json.error + "</p>");
-          }
-        });
-      })(this)
-      </script>
-    %else:
-      ## If the user is not authenticated, clicking the enroll button pops up the register
-      ## field. We also slip in the registration fields into the login/register fields so
-      ## the user is automatically registered after logging in / registering
-      <script type="text/javascript">
-      (function() {
-        $(".register").click(function() {
-          if ($(".login_form .enroll_fieldset").length === 0) {
-            $(".login_form").append( $(".enroll_fieldset").first().clone() );
-          }
-          if ($(".register_form .enroll_fieldset").length === 0) {
-            $(".register_form").append( $(".enroll_fieldset").first().clone() );
-          }
-        });
-      })(this)
-      </script>
-    %endif
-  %endif
+    $('#class_enroll_form').on('ajax:complete', function(event, xhr) {
+      if(xhr.status == 200) {
+        location.href = "${reverse('dashboard')}";
+      } else if (xhr.status == 403) {
+        location.href = "${reverse('register_user')}?course_id=${course.id}&enrollment_action=enroll";
+      } else {
+        $('#register_error').html(
+            (xhr.responseText ? xhr.responseText : 'An error occurred. Please try again later.')
+        ).css("display", "block");
+      }
+    });
+  })(this)
+  </script>
 
   <script src="${static.url('js/course_info.js')}"></script>
 </%block>
@@ -66,8 +50,7 @@
         </hgroup>
 
         <div class="main-cta">
-        %if user.is_authenticated():
-            %if registered:
+        %if user.is_authenticated() and registered:
 	              %if show_courseware_link:
                     <a href="${course_target}">
                 %endif
@@ -76,16 +59,9 @@
                     <strong>View Courseware</strong>
                     </a>
                 %endif
-            %else:
-               <a href="#" class="register">Register for ${course.number}</a>
-	             <div id="register_message"></div>
-            %endif
         %else:
-            <a href="#signup-modal" class="register" rel="leanModal" data-notice='You must Sign Up
-% if not settings.MITX_FEATURES['DISABLE_LOGIN_BUTTON']:
-		     or <a href="#login-modal" rel="leanModal">Log In</a>
-% endif
-		     to enroll.'>Register for ${course.number}</a>
+            <a href="#" class="register">Register for ${course.number}</a>
+            <div id="register_error"></div>
         %endif
         </div>
 
diff --git a/lms/templates/dashboard.html b/lms/templates/dashboard.html
index d23609801f..d9eca70e4d 100644
--- a/lms/templates/dashboard.html
+++ b/lms/templates/dashboard.html
@@ -59,14 +59,16 @@
       $("#unenroll_course_number").text( $(event.target).data("course-number") );
     });
 
-    $(document).delegate('#unenroll_form', 'ajax:success', function(data, json, xhr) {
-      if(json.success) {
-        location.href="${reverse('dashboard')}";
+    $('#unenroll_form').on('ajax:complete', function(event, xhr) {
+      if(xhr.status == 200) {
+        location.href = "${reverse('dashboard')}";
+      } else if (xhr.status == 403) {
+        location.href = "${reverse('signin_user')}?course_id=" +
+          $("#unenroll_course_id").val() + "&enrollment_action=unenroll";
       } else {
-        if($('#unenroll_error').length == 0) {
-          $('#unenroll_form').prepend('<div id="unenroll_error" class="modal-form-error"></div>');
-        }
-        $('#unenroll_error').text(json.error).stop().css("display", "block");
+        $('#unenroll_error').html(
+          xhr.responseText ? xhr.responseText : "An error occurred. Please try again later."
+        ).stop().css("display", "block");
       }
     });
 
@@ -355,6 +357,8 @@
       <hr/>
     </header>
 
+    <div id="unenroll_error" class="modal-form-error"></div>
+
     <form id="unenroll_form" method="post" data-remote="true" action="${reverse('change_enrollment')}">
       <input name="course_id" id="unenroll_course_id" type="hidden" />
       <input name="enrollment_action" type="hidden" value="unenroll" />
diff --git a/lms/templates/login.html b/lms/templates/login.html
index 2e0281f4f6..2cfb40d6bc 100644
--- a/lms/templates/login.html
+++ b/lms/templates/login.html
@@ -126,6 +126,11 @@
         </ol>
       </fieldset>
 
+% if course_id and enrollment_action:
+      <input type="hidden" name="enrollment_action" value="${enrollment_action | h}" />
+      <input type="hidden" name="course_id" value="${course_id | h}" />
+% endif
+
       <div class="form-actions">
         <button name="submit" type="submit" id="submit" class="action action-primary action-update">Log into My edX Account <span class="orn-plus">+</span> Access My Courses</button>
       </div>
diff --git a/lms/templates/register.html b/lms/templates/register.html
index ee06a3caa0..663bfd14d5 100644
--- a/lms/templates/register.html
+++ b/lms/templates/register.html
@@ -213,6 +213,11 @@
         </ol>
       </fieldset>
 
+% if course_id and enrollment_action:
+      <input type="hidden" name="enrollment_action" value="${enrollment_action | h}" />
+      <input type="hidden" name="course_id" value="${course_id | h}" />
+% endif
+
       <div class="form-actions">
         <button name="submit" type="submit" id="submit" class="action action-primary action-update">Register <span class="orn-plus">+</span> Create My Account</button>
       </div>
diff --git a/lms/urls.py b/lms/urls.py
index 49dae19d58..fd76e7fcdf 100644
--- a/lms/urls.py
+++ b/lms/urls.py
@@ -180,7 +180,7 @@ if settings.COURSEWARE_ENABLED:
 
         url(r'^courses/?$', 'branding.views.courses', name="courses"),
         url(r'^change_enrollment$',
-            'student.views.change_enrollment_view', name="change_enrollment"),
+            'student.views.change_enrollment', name="change_enrollment"),
 
         #About the course
         url(r'^courses/(?P<course_id>[^/]+/[^/]+/[^/]+)/about$',