diff --git a/IPython/html/static/notebook/js/cell.js b/IPython/html/static/notebook/js/cell.js
index cd1ac7e..959f21f 100644
--- a/IPython/html/static/notebook/js/cell.js
+++ b/IPython/html/static/notebook/js/cell.js
@@ -322,8 +322,8 @@ var IPython = (function (IPython) {
                 }
             }
         }
-        // fallback on default (python)
-        var default_mode = this.default_mode || 'text/plain';
+        // fallback on default
+        var default_mode = this._options.cm_config.mode || 'text/plain';
         this.code_mirror.setOption('mode', default_mode);
     };
 
diff --git a/IPython/html/static/notebook/js/codecell.js b/IPython/html/static/notebook/js/codecell.js
index 421bbbe..9c18caf 100644
--- a/IPython/html/static/notebook/js/codecell.js
+++ b/IPython/html/static/notebook/js/codecell.js
@@ -65,7 +65,6 @@ var IPython = (function (IPython) {
         this.code_mirror = null;
         this.input_prompt_number = null;
         this.collapsed = false;
-        this.default_mode = 'ipython';
         this.cell_type = "code";