Refactored to JS standards. Fixed Attribution.

thisStyle      --> this_style.
function foo() --> var foo = function()

StackExchange improperly attributed for Davide Cervone's
Markdown+MathJax handling.  This has been fixed.

Ref:
http://stackoverflow.com/a/11231030/122022
http://www.math.union.edu/~dpvc/transfer/mathjax/mathjax-editing.js

IPython/frontend/html/notebook/static/js/mathjaxutils.js

@@ -1,239 +1,243 b''
 //----------------------------------------------------------------------------
 //  Copyright (C) 2008-2012  The IPython Development Team
 //
 //  Distributed under the terms of the BSD License.  The full license is in
 //  the file COPYING, distributed as part of this software.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // MathJax utility functions
 //============================================================================
 
 IPython.namespace('IPython.mathjaxutils');
 
 IPython.mathjaxutils = (function (IPython) {
 
     var init = function () {
         if (window.MathJax) { 
             // MathJax loaded
             MathJax.Hub.Config({
                 TeX: { equationNumbers: { autoNumber: "AMS", useLabelIds: true } },
                 tex2jax: {
                     inlineMath: [ ['$','$'], ["\\(","\\)"] ],
                     displayMath: [ ['$$','$$'], ["\\[","\\]"] ],
                     processEnvironments: true
                 },
                 displayAlign: 'left', // Change this to 'center' to center equations.
                 "HTML-CSS": {
                     styles: {'.MathJax_Display': {"margin": 0}}
                 }
             });
         } else if (window.mathjax_url != "") {
             // Don't have MathJax, but should. Show dialog.
             var dialog = $('<div></div>')
                 .append(
                     $("<p></p>").addClass('dialog').html(
                         "Math/LaTeX rendering will be disabled."
                     )
                 ).append(
                     $("<p></p>").addClass('dialog').html(
                         "If you have administrative access to the notebook server and" +
                         " a working internet connection, you can install a local copy" +
                         " of MathJax for offline use with the following command on the server" +
                         " at a Python or IPython prompt:"
                     )
                 ).append(
                     $("<pre></pre>").addClass('dialog').html(
                         ">>> from IPython.external import mathjax; mathjax.install_mathjax()"
                     )
                 ).append(
                     $("<p></p>").addClass('dialog').html(
                         "This will try to install MathJax into the IPython source directory."
                     )
                 ).append(
                     $("<p></p>").addClass('dialog').html(
                         "If IPython is installed to a location that requires" +
                         " administrative privileges to write, you will need to make this call as" +
                         " an administrator, via 'sudo'."
                     )
                 ).append(
                     $("<p></p>").addClass('dialog').html(
                         "When you start the notebook server, you can instruct it to disable MathJax support altogether:"
                     )
                 ).append(
                     $("<pre></pre>").addClass('dialog').html(
                         "$ ipython notebook --no-mathjax"
                     )
                 ).append(
                     $("<p></p>").addClass('dialog').html(
                         "which will prevent this dialog from appearing."
                     )
                 ).dialog({
                     title: "Failed to retrieve MathJax from '" + window.mathjax_url + "'",
                     width: "70%",
                     modal: true,
                 })
         } else {
             // No MathJax, but none expected. No dialog.
         };
     };
 
-    // Some magic for deferring mathematical expressions to MathJaX
-    // Some of the code here is adapted with permission from Stack Exchange Inc.
+    // Some magic for deferring mathematical expressions to MathJax
+    // by hiding them from the Markdown parser.
+    // Some of the code here is adapted with permission from Davide Cervone
+    // under the terms of the Apache2 license governing the MathJax project.
+    // Other minor modifications are also due to StackExchange and are used with
+    // permission.
 
     var inline = "$"; // the inline math delimiter
     var blocks, start, end, last, braces; // used in searching for math
     var math; // stores math until pagedown (Markdown parser) is done
     var HUB = MathJax.Hub;
 
     // MATHSPLIT contains the pattern for math delimiters and special symbols
     // needed for searching for math in the text input.   
     var MATHSPLIT = /(\$\$?|\\(?:begin|end)\{[a-z]*\*?\}|\\[\\{}$]|[{}]|(?:\n\s*)+|@@\d+@@)/i;
 
     //  The math is in blocks i through j, so 
     //    collect it into one block and clear the others.
     //  Replace &, <, and > by named entities.
     //  For IE, put <br> at the ends of comments since IE removes \n.
     //  Clear the current math positions and store the index of the
     //    math, then push the math string onto the storage array.
     //  The preProcess function is called on all blocks if it has been passed in
-    function processMath(i, j, preProcess) {
+    var process_math = function (i, j, pre_process) {
         var block = blocks.slice(i, j + 1).join("").replace(/&/g, "&amp;") // use HTML entity for &
         .replace(/</g, "&lt;") // use HTML entity for <
         .replace(/>/g, "&gt;") // use HTML entity for >
         ;
         if (HUB.Browser.isMSIE) {
             block = block.replace(/(%[^\n]*)\n/g, "$1<br/>\n")
         }
         while (j > i) {
             blocks[j] = "";
             j--;
         }
         blocks[i] = "@@" + math.length + "@@"; // replace the current block text with a unique tag to find later
-        if (preProcess)
-            block = preProcess(block);
+        if (pre_process)
+            block = pre_process(block);
         math.push(block);
         start = end = last = null;
     }
 
     //  Break up the text into its component parts and search
     //    through them for math delimiters, braces, linebreaks, etc.
     //  Math delimiters must match and braces must balance.
     //  Don't allow math to pass through a double linebreak
     //    (which will be a paragraph).
     //
-    function removeMath(text) {
+    var remove_math = function (text) {
         start = end = last = null; // for tracking math delimiters
         math = []; // stores math strings for later
         
         // Except for extreme edge cases, this should catch precisely those pieces of the markdown
         // source that will later be turned into code spans. While MathJax will not TeXify code spans,
         // we still have to consider them at this point; the following issue has happened several times:
         //
         //     `$foo` and `$bar` are varibales.  -->  <code>$foo ` and `$bar</code> are variables.
 
         var hasCodeSpans = /`/.test(text),
-            deTilde;
+            de_tilde;
         if (hasCodeSpans) {
             text = text.replace(/~/g, "~T").replace(/(^|[^\\])(`+)([^\n]*?[^`\n])\2(?!`)/gm, function (wholematch) {
                 return wholematch.replace(/\$/g, "~D");
             });
-            deTilde = function (text) { return text.replace(/~([TD])/g, function (wholematch, character) { return { T: "~", D: "$" }[character]; }) };
+            de_tilde = function (text) { return text.replace(/~([TD])/g, function (wholematch, character) { return { T: "~", D: "$" }[character]; }) };
         } else {
-            deTilde = function (text) { return text; };
+            de_tilde = function (text) { return text; };
         }
         
         blocks = IPython.utils.regex_split(text.replace(/\r\n?/g, "\n"),MATHSPLIT);
 
         for (var i = 1, m = blocks.length; i < m; i += 2) {
             var block = blocks[i];
             if (block.charAt(0) === "@") {
                 //
                 //  Things that look like our math markers will get
                 //  stored and then retrieved along with the math.
                 //
                 blocks[i] = "@@" + math.length + "@@";
                 math.push(block);
             }
             else if (start) {
                 //
                 //  If we are in math, look for the end delimiter,
                 //    but don't go past double line breaks, and
                 //    and balance braces within the math.
                 //
                 if (block === end) {
                     if (braces) {
                         last = i
                     }
                     else {
-                        processMath(start, i, deTilde)
+                        process_math(start, i, de_tilde)
                     }
                 }
                 else if (block.match(/\n.*\n/)) {
                     if (last) {
                         i = last;
-                        processMath(start, i, deTilde)
+                        process_math(start, i, de_tilde)
                     }
                     start = end = last = null;
                     braces = 0;
                 }
                 else if (block === "{") {
                     braces++
                 }
                 else if (block === "}" && braces) {
                     braces--
                 }
             }
             else {
                 //
                 //  Look for math start delimiters and when
                 //    found, set up the end delimiter.
                 //
                 if (block === inline || block === "$$") {
                     start = i;
                     end = block;
                     braces = 0;
                 }
                 else if (block.substr(1, 5) === "begin") {
                     start = i;
                     end = "\\end" + block.substr(6);
                     braces = 0;
                 }
             }
         }
         if (last) {
-            processMath(start, last, deTilde)
+            process_math(start, last, de_tilde)
         }
-        return deTilde(blocks.join(""));
+        return de_tilde(blocks.join(""));
     }
 
     //
     //  Put back the math strings that were saved,
     //    and clear the math array (no need to keep it around).
     //  
-    function replaceMath(text) {
+    var replace_math = function (text) {
         text = text.replace(/@@(\d+)@@/g, function (match, n) {
             return math[n]
         });
         math = null;
         return text;
     }
 
-    function queueRender() {
+    var queue_render = function () {
         // see https://groups.google.com/forum/?fromgroups=#!topic/mathjax-users/cpwy5eCH1ZQ
         MathJax.Hub.Queue( 
           ["resetEquationNumbers",MathJax.InputJax.TeX], 
           ["PreProcess",MathJax.Hub], 
           ["Reprocess",MathJax.Hub] 
           ); 
     }
 
     return {
         init : init,
-        processMath : processMath,
-        removeMath : removeMath,
-        replaceMath : replaceMath,
-        queueRender : queueRender
+        process_math : process_math,
+        remove_math : remove_math,
+        replace_math : replace_math,
+        queue_render : queue_render
     };
 
 }(IPython));
  No newline at end of file

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

@@ -1,421 +1,421 b''
 //----------------------------------------------------------------------------
 //  Copyright (C) 2008-2012  The IPython Development Team
 //
 //  Distributed under the terms of the BSD License.  The full license is in
 //  the file COPYING, distributed as part of this software.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // TextCell
 //============================================================================
 
 var IPython = (function (IPython) {
 
     // TextCell base class
     var key = IPython.utils.keycodes;
 
     var TextCell = function () {
         this.code_mirror_mode = this.code_mirror_mode || 'htmlmixed';
         IPython.Cell.apply(this, arguments);
         this.rendered = false;
         this.cell_type = this.cell_type || 'text';
     };
 
 
     TextCell.prototype = new IPython.Cell();
 
 
     TextCell.prototype.create_element = function () {
         var cell = $("<div>").addClass('cell text_cell border-box-sizing');
         cell.attr('tabindex','2');
         var input_area = $('<div/>').addClass('text_cell_input border-box-sizing');
         this.code_mirror = CodeMirror(input_area.get(0), {
             indentUnit : 4,
             mode: this.code_mirror_mode,
             theme: 'default',
             value: this.placeholder,
             readOnly: this.read_only,
             lineWrapping : true,
             extraKeys: {"Tab": "indentMore","Shift-Tab" : "indentLess"},
             onKeyEvent: $.proxy(this.handle_codemirror_keyevent,this)
         });
         // The tabindex=-1 makes this div focusable.
         var render_area = $('<div/>').addClass('text_cell_render border-box-sizing').
             addClass('rendered_html').attr('tabindex','-1');
         cell.append(input_area).append(render_area);
         this.element = cell;
     };
 
 
     TextCell.prototype.bind_events = function () {
         IPython.Cell.prototype.bind_events.apply(this);
         var that = this;
         this.element.keydown(function (event) {
             if (event.which === 13 && !event.shiftKey) {
                 if (that.rendered) {
                     that.edit();
                     return false;
                 };
             };
         });
         this.element.dblclick(function () {
             that.edit();
         });
     };
 
 
     TextCell.prototype.handle_codemirror_keyevent = function (editor, event) {
         // This method gets called in CodeMirror's onKeyDown/onKeyPress
         // handlers and is used to provide custom key handling. Its return
         // value is used to determine if CodeMirror should ignore the event:
         // true = ignore, false = don't ignore.
         
         if (event.keyCode === 13 && (event.shiftKey || event.ctrlKey)) {
             // Always ignore shift-enter in CodeMirror as we handle it.
             return true;
         }
         return false;
     };
 
 
     TextCell.prototype.select = function () {
         IPython.Cell.prototype.select.apply(this);
         var output = this.element.find("div.text_cell_render");
         output.trigger('focus');
     };
 
 
     TextCell.prototype.unselect = function() {
         // render on selection of another cell
         this.render();
         IPython.Cell.prototype.unselect.apply(this);
     };
 
 
     TextCell.prototype.edit = function () {
         if ( this.read_only ) return;
         if (this.rendered === true) {
             var text_cell = this.element;
             var output = text_cell.find("div.text_cell_render");  
             output.hide();
             text_cell.find('div.text_cell_input').show();
             this.code_mirror.refresh();
             this.code_mirror.focus();
             // We used to need an additional refresh() after the focus, but
             // it appears that this has been fixed in CM. This bug would show
             // up on FF when a newly loaded markdown cell was edited.
             this.rendered = false;
             if (this.get_text() === this.placeholder) {
                 this.set_text('');
                 this.refresh();
             }
         }
     };
 
 
     // Subclasses must define render.
     TextCell.prototype.render = function () {};
 
 
     TextCell.prototype.get_text = function() {
         return this.code_mirror.getValue();
     };
 
 
     TextCell.prototype.set_text = function(text) {
         this.code_mirror.setValue(text);
         this.code_mirror.refresh();
     };
 
 
     TextCell.prototype.get_rendered = function() {
         return this.element.find('div.text_cell_render').html();
     };
 
 
     TextCell.prototype.set_rendered = function(text) {
         this.element.find('div.text_cell_render').html(text);
     };
 
 
     TextCell.prototype.at_top = function () {
         if (this.rendered) {
             return true;
         } else {
             return false;
         }
     };
 
 
     TextCell.prototype.at_bottom = function () {
         if (this.rendered) {
             return true;
         } else {
             return false;
         }
     };
 
 
     TextCell.prototype.fromJSON = function (data) {
         IPython.Cell.prototype.fromJSON.apply(this, arguments);
         if (data.cell_type === this.cell_type) {
             if (data.source !== undefined) {
                 this.set_text(data.source);
                 // make this value the starting point, so that we can only undo
                 // to this state, instead of a blank cell
                 this.code_mirror.clearHistory();
                 this.set_rendered(data.rendered || '');
                 this.rendered = false;
                 this.render();
             }
         }
     };
 
 
     TextCell.prototype.toJSON = function () {
         var data = IPython.Cell.prototype.toJSON.apply(this);
         data.cell_type = this.cell_type;
         data.source = this.get_text();
         return data;
     };
 
 
     // HTMLCell
 
     var HTMLCell = function () {
         this.placeholder = "Type <strong>HTML</strong> and LaTeX: $\\alpha^2$";
         IPython.TextCell.apply(this, arguments);
         this.cell_type = 'html';
     };
 
 
     HTMLCell.prototype = new TextCell();
 
 
     HTMLCell.prototype.render = function () {
         if (this.rendered === false) {
             var text = this.get_text();
             if (text === "") { text = this.placeholder; }
             this.set_rendered(text);
             this.typeset();
             this.element.find('div.text_cell_input').hide();
             this.element.find("div.text_cell_render").show();
             this.rendered = true;
         }
     };
 
 
     // MarkdownCell
 
     var MarkdownCell = function () {
         this.placeholder = "Type *Markdown* and LaTeX: $\\alpha^2$";
         IPython.TextCell.apply(this, arguments);
         this.cell_type = 'markdown';
     };
 
 
     MarkdownCell.prototype = new TextCell();
 
 
     MarkdownCell.prototype.render = function () {
         if (this.rendered === false) {
             var text = this.get_text();
             if (text === "") { text = this.placeholder; }
 
-            text = IPython.mathjaxutils.removeMath(text)
+            text = IPython.mathjaxutils.remove_math(text)
             var html = IPython.markdown_converter.makeHtml(text);
-            html = IPython.mathjaxutils.replaceMath(html)
+            html = IPython.mathjaxutils.replace_math(html)
 
             try {
                 this.set_rendered(html);
             } catch (e) {
                 console.log("Error running Javascript in Markdown:");
                 console.log(e);
                 this.set_rendered($("<div/>").addClass("js-error").html(
                     "Error rendering Markdown!<br/>" + e.toString())
                 );
             }
             this.typeset()
             this.element.find('div.text_cell_input').hide();
             this.element.find("div.text_cell_render").show();
             var code_snippets = this.element.find("pre > code");
             code_snippets.replaceWith(function () {
                 var code = $(this).html();
                 /* Substitute br for newlines and &nbsp; for spaces
                    before highlighting, since prettify doesn't
                    preserve those on all browsers */
                 code = code.replace(/(\r\n|\n|\r)/gm, "<br/>");
                 code = code.replace(/ /gm, '&nbsp;');
                 code = prettyPrintOne(code);
 
                 return '<code class="prettyprint">' + code + '</code>';
             });
 
-            IPython.mathjaxutils.queueRender()
+            IPython.mathjaxutils.queue_render()
             this.rendered = true;
         }
     };
 
 
     // RawCell
 
     var RawCell = function () {
         this.placeholder = "Type plain text and LaTeX: $\\alpha^2$";
         this.code_mirror_mode = 'rst';
         IPython.TextCell.apply(this, arguments);
         this.cell_type = 'raw';
         var that = this
 
         this.element.focusout(
                 function() { that.auto_highlight(); }
             );
     };
 
 
     RawCell.prototype = new TextCell();
 
     RawCell.prototype.auto_highlight = function () {
         this._auto_highlight(IPython.config.raw_cell_highlight);
     };
 
     RawCell.prototype.render = function () {
         this.rendered = true;
         this.edit();
     };
 
 
     RawCell.prototype.handle_codemirror_keyevent = function (editor, event) {
         // This method gets called in CodeMirror's onKeyDown/onKeyPress
         // handlers and is used to provide custom key handling. Its return
         // value is used to determine if CodeMirror should ignore the event:
         // true = ignore, false = don't ignore.
 
         var that = this;
         if (event.which === key.UPARROW && event.type === 'keydown') {
             // If we are not at the top, let CM handle the up arrow and
             // prevent the global keydown handler from handling it.
             if (!that.at_top()) {
                 event.stop();
                 return false;
             } else {
                 return true;
             };
         } else if (event.which === key.DOWNARROW && event.type === 'keydown') {
             // If we are not at the bottom, let CM handle the down arrow and
             // prevent the global keydown handler from handling it.
             if (!that.at_bottom()) {
                 event.stop();
                 return false;
             } else {
                 return true;
             };
         };
         return false;
     };
 
 
     RawCell.prototype.select = function () {
         IPython.Cell.prototype.select.apply(this);
         this.code_mirror.refresh();
         this.code_mirror.focus();
     };
 
 
     RawCell.prototype.at_top = function () {
         var cursor = this.code_mirror.getCursor();
         if (cursor.line === 0 && cursor.ch === 0) {
             return true;
         } else {
             return false;
         }
     };
 
 
     RawCell.prototype.at_bottom = function () {
         var cursor = this.code_mirror.getCursor();
         if (cursor.line === (this.code_mirror.lineCount()-1) && cursor.ch === this.code_mirror.getLine(cursor.line).length) {
             return true;
         } else {
             return false;
         }
     };
 
 
     // HTMLCell
 
     var HeadingCell = function () {
         this.placeholder = "Type Heading Here";
         IPython.TextCell.apply(this, arguments);
         this.cell_type = 'heading';
         this.level = 1;
     };
 
 
     HeadingCell.prototype = new TextCell();
 
 
     HeadingCell.prototype.fromJSON = function (data) {
         if (data.level != undefined){
             this.level = data.level;
         }
         IPython.TextCell.prototype.fromJSON.apply(this, arguments);
     };
 
 
     HeadingCell.prototype.toJSON = function () {
         var data = IPython.TextCell.prototype.toJSON.apply(this);
         data.level = this.get_level();
         return data;
     };
 
 
     HeadingCell.prototype.set_level = function (level) {
         this.level = level;
         if (this.rendered) {
             this.rendered = false;
             this.render();
         };
     };
 
 
     HeadingCell.prototype.get_level = function () {
         return this.level;
     };
 
 
     HeadingCell.prototype.set_rendered = function (text) {
         var r = this.element.find("div.text_cell_render");
         r.empty();
         r.append($('<h'+this.level+'/>').html(text));
     };
 
 
     HeadingCell.prototype.get_rendered = function () {
         var r = this.element.find("div.text_cell_render");
         return r.children().first().html();
     };
 
 
     HeadingCell.prototype.render = function () {
         if (this.rendered === false) {
             var text = this.get_text();
             if (text === "") { text = this.placeholder; }
             this.set_rendered(text);
             this.typeset();
             this.element.find('div.text_cell_input').hide();
             this.element.find("div.text_cell_render").show();
             this.rendered = true;
         };
     };
 
     IPython.TextCell = TextCell;
     IPython.HTMLCell = HTMLCell;
     IPython.MarkdownCell = MarkdownCell;
     IPython.RawCell = RawCell;
     IPython.HeadingCell = HeadingCell;
 
 
     return IPython;
 
 }(IPython));