Markdown in heading cells (take 2)

small typo prevented the previous implementation from working.

This also moves the rendering to the 'render' method,
away from set_rendered.

closes  #3053

(again)

IPython/html/static/notebook/js/textcell.js

@@ -27,7 +27,7 b' var IPython = (function (IPython) {'
      *
      * @class TextCell
      * @constructor TextCell
-     * @extend Ipython.Cell
+     * @extend IPython.Cell
      * @param {object|undefined} [options]
      *      @param [options.cm_config] {object} config to pass to CodeMirror, will extend/overwrite default config
      *      @param [options.placeholder] {string} default string to use when souce in empty for rendering (only use in some TextCell subclass)
@@ -285,7 +285,7 b' var IPython = (function (IPython) {'
     /**
      * @class MarkdownCell
      * @constructor MarkdownCell
-     * @extends Ipython.HtmlCell
+     * @extends IPython.HTMLCell
      */
     var MarkdownCell = function (options) {
         var options = options || {};
@@ -342,7 +342,7 b' var IPython = (function (IPython) {'
     /**
      * @class RawCell
      * @constructor RawCell
-     * @extends Ipython.TextCell
+     * @extends IPython.TextCell
      */
     var RawCell = function (options) {
 
@@ -437,12 +437,12 b' var IPython = (function (IPython) {'
 
     /**
      * @class HeadingCell
-     * @extends Ipython.TextCell
+     * @extends IPython.TextCell
      */
 
     /**
      * @constructor HeadingCell
-     * @extends Ipython.TextCell
+     * @extends IPython.TextCell
      */
     var HeadingCell = function (options) {
 
@@ -501,24 +501,8 b' var IPython = (function (IPython) {'
     };
 
 
-    HeadingCell.prototype.set_rendered = function (text) {
-        var r = this.element.find("div.text_cell_render");
-        r.empty();
-        var link = text.replace(/ /g, '_');
-        r.append(
-            $('<h'+this.level+'/>')
-            .append(
-            $('<a/>')
-                .addClass('heading-anchor')
-                .attr('id', link)
-                .html(text)
-            ).append(
-            $('<a/>')
-                .addClass('anchor-link')
-                .attr('href', '#' + link)
-                .text('¶')
-            )
-        );
+    HeadingCell.prototype.set_rendered = function (html) {
+        this.element.find("div.text_cell_render").html(html);
     };
 
 
@@ -532,7 +516,28 b' var IPython = (function (IPython) {'
         if (this.rendered === false) {
             var text = this.get_text();
             if (text === "") { text = this.placeholder; }
-            this.set_rendered(text);
+            text = Array(this.level + 1).join("#") + " " + text;
+            text = IPython.mathjaxutils.remove_math(text);
+            var html = marked.parser(marked.lexer(text));
+            var h = $(IPython.mathjaxutils.replace_math(html));
+            // move the markdown-rendered html down one level,
+            // into an anchor tag for linking
+            html = h.html();
+            var hash = h.text().replace(/ /g, '_');
+            h.empty();
+            var a = $('<a/>')
+                .addClass('heading-anchor')
+                .html(html)
+                .attr('id', hash);
+            // and append two anchors (one with the text, one clickable)
+            h.append(a).append(
+                $('<a/>')
+                    .addClass('anchor-link')
+                    .attr('href', '#' + hash)
+                    .text('¶')
+            );
+            
+            this.set_rendered(h);
             this.typeset();
             this.element.find('div.text_cell_input').hide();
             this.element.find("div.text_cell_render").show();