diff --git a/kallithea/controllers/compare.py b/kallithea/controllers/compare.py
--- a/kallithea/controllers/compare.py
+++ b/kallithea/controllers/compare.py
@@ -192,9 +192,9 @@ class CompareController(BaseRepoControll
         c.fulldiff = request.GET.get('fulldiff')
         # partial uses compare_cs.html template directly
         partial = request.environ.get('HTTP_X_PARTIAL_XHR')
-        # as_form puts hidden input field with changeset revisions
-        c.as_form = partial and request.GET.get('as_form')
-        # swap url for compare_diff page - never partial and never as_form
+        # is_ajax_preview puts hidden input field with changeset revisions
+        c.is_ajax_preview = partial and request.GET.get('is_ajax_preview')
+        # swap url for compare_diff page - never partial and never is_ajax_preview
         c.swap_url = h.url('compare_url',
             repo_name=c.cs_repo.repo_name,
             org_ref_type=other_ref_type, org_ref_name=other_ref_name,
diff --git a/kallithea/controllers/pullrequests.py b/kallithea/controllers/pullrequests.py
--- a/kallithea/controllers/pullrequests.py
+++ b/kallithea/controllers/pullrequests.py
@@ -637,7 +637,7 @@ class PullrequestsController(BaseRepoCon
          ) = cs_model.calculate_pull_request_result(c.pull_request)
         c.changeset_statuses = ChangesetStatus.STATUSES
 
-        c.as_form = False
+        c.is_ajax_preview = False
         c.ancestors = None # [c.a_rev] ... but that is shown in an other way
         return render('/pullrequests/pullrequest_show.html')
 
diff --git a/kallithea/templates/compare/compare_cs.html b/kallithea/templates/compare/compare_cs.html
--- a/kallithea/templates/compare/compare_cs.html
+++ b/kallithea/templates/compare/compare_cs.html
@@ -94,7 +94,7 @@
 
     </div>
 
-    %if c.as_form:
+    %if c.is_ajax_preview:
       <h5>
       ## links should perhaps use ('rev', c.a_rev) instead ...
       ${h.link_to(_('Show merge diff'),
@@ -120,7 +120,7 @@
   %endif
 </div>
 
-%if c.as_form:
+%if c.is_ajax_preview:
 <div id="jsdata" style="display:none">${h.js(c.jsdata)}</div>
 %else:
 <script type="text/javascript" src="${h.url('/js/graph.js', ver=c.kallithea_version)}"></script>
@@ -129,7 +129,7 @@
 <script type="text/javascript">
 
     $(document).ready(function(){
-%if not c.as_form:
+%if not c.is_ajax_preview:
         var jsdata = ${h.js(c.jsdata)};
         var r = new BranchRenderer('graph_canvas', 'graph_content_pr', 'chg_');
         r.render(jsdata);
diff --git a/kallithea/templates/pullrequests/pullrequest.html b/kallithea/templates/pullrequests/pullrequest.html
--- a/kallithea/templates/pullrequests/pullrequest.html
+++ b/kallithea/templates/pullrequests/pullrequest.html
@@ -147,7 +147,7 @@ ${self.repo_context_bar('showpullrequest
                          other_repo='__org_repo__',
                          other_ref_type='rev',
                          other_ref_name='__org_ref_name__',
-                         as_form=True,
+                         is_ajax_preview=True,
                          merge=True,
                          ))};
       var org_repo = $('#pull_request_form #org_repo').val();
diff --git a/kallithea/tests/functional/test_compare_local.py b/kallithea/tests/functional/test_compare_local.py
--- a/kallithea/tests/functional/test_compare_local.py
+++ b/kallithea/tests/functional/test_compare_local.py
@@ -189,7 +189,7 @@ class TestCompareController(TestControll
         ## files
         response.mustcontain("""<a href="#C--c8e92ef85cd1">.hgignore</a>""")
 
-    def test_compare_revisions_hg_as_form(self):
+    def test_compare_revisions_hg_is_ajax_preview(self):
         self.log_user()
         rev1 = 'b986218ba1c9'
         rev2 = '3d8f361e72ab'
@@ -200,7 +200,7 @@ class TestCompareController(TestControll
                                     org_ref_name=rev1,
                                     other_ref_type="rev",
                                     other_ref_name=rev2,
-                                    as_form=True,
+                                    is_ajax_preview=True,
                                     ),
                                 extra_environ={'HTTP_X_PARTIAL_XHR': '1'},)
 
@@ -210,7 +210,7 @@ class TestCompareController(TestControll
         response.mustcontain('Merge Ancestor')
         response.mustcontain("""<a class="changeset_hash" href="/%s/changeset/b986218ba1c9b0d6a259fac9b050b1724ed8e545">%s</a>""" % (HG_REPO, rev1))
 
-    def test_compare_revisions_git_as_form(self):
+    def test_compare_revisions_git_is_ajax_preview(self):
         self.log_user()
         rev1 = 'c1214f7e79e02fc37156ff215cd71275450cffc3'
         rev2 = '38b5fe81f109cb111f549bfe9bb6b267e10bc557'
@@ -221,7 +221,7 @@ class TestCompareController(TestControll
                                     org_ref_name=rev1,
                                     other_ref_type="rev",
                                     other_ref_name=rev2,
-                                    as_form=True,
+                                    is_ajax_preview=True,
                                     ),
                                 extra_environ={'HTTP_X_PARTIAL_XHR': '1'},)
         ## outgoing changesets between those revisions