Implement MathJax support

* lisp/org-exp.el (org-export-with-LaTeX-fragments): New default t, which
now means to use MathJax processing for HTML.  Also allow new value
`dvipng' to force the old image processing.
(org-infile-export-plist): Parse for MATHJAX setup line.
* lisp/org-html.el (org-export-html-mathjax-options): New option.
(org-export-html-mathjax-config): New function.
(org-export-html-mathjax-template): New option.
(org-export-html-preprocess): Call the LaTeX snippet processor with an
additional argument to declare special ways of processing.
(org-export-as-html): Bind the dynamical variable
`org-export-have-math'.  Insert the MathJax script template when it is
needed by the document.
* lisp/org.el (org-preview-latex-fragment): Call `org-format-latex' with
the additional processing argument.
(org-export-have-math): New variable, for dynamic scoping.
(org-format-latex): Implement specific ways of processing.  New
function argument for processing type.
(org-org-menu): Remove the entry to configure LaTeX snippet
processing.

MathJax is now the default for displaying math in a browser.

doc/org.texi

@@ -363,6 +363,7 @@ HTML export
 * Links in HTML export::	How links will be interpreted and formatted
 * Tables in HTML export::	How to modify the formatting of tables
 * Images in HTML export::	How to insert figures into HTML output
+* Math formatting in HTML export::  Beautiful math also on the web
 * Text areas in HTML export::	An alternative way to show an example
 * CSS support::			Changing the appearance of the output
 * JavaScript support::		Info and Folding in a web browser
@@ -439,12 +440,17 @@ Using header arguments
 Specific header arguments
 
 * var::				Pass arguments to code blocks
-* results::			Specify the type of results and how they will be collected and handled
+* results::			Specify the type of results and how they will
+                                be collected and handled
 * file::			Specify a path for file output
-* dir::	                        Specify the default directory for code block execution
+* dir::				Specify the default (possibly remote)
+                                directory for code block execution
 * exports::			Export code and/or results
 * tangle::			Toggle tangling and specify file name
-* no-expand::			Turn off variable assignment and noweb expansion during tangling
+* comments::			Toggle insertion of comments in tangled
+                                code files
+* no-expand::			Turn off variable assignment and noweb
+                                expansion during tangling
 * session::			Preserve the state of code evaluation
 * noweb::			Toggle expansion of noweb references
 * cache::			Avoid re-evaluating unchanged code blocks
@@ -452,6 +458,7 @@ Specific header arguments
 * colnames::			Handle column names in tables
 * rownames::			Handle row names in tables
 * shebang::			Make tangled files executable
+* eval::			Limit evaluation of specific code blocks
 
 Miscellaneous
 
@@ -8818,12 +8825,9 @@ is a macro system based on Donald E. Knuth's @TeX{} system.  Many of the
 features described here as ``La@TeX{}'' are really from @TeX{}, but for
 simplicity I am blurring this distinction.}  is widely used to typeset
 scientific documents. Org-mode supports embedding La@TeX{} code into its
-files, because many academics are used to reading La@TeX{} source code, and
+files, because many academics are used to writing and reading La@TeX{} source
-because it can be readily processed into images for HTML production.
+code, and because it can be readily processed to produce pretty output for a
-
+number of export backends.
-It is not necessary to mark La@TeX{} macros and code in any special way.
-If you observe a few conventions, Org-mode knows how to find it and what
-to do with it.
 
 @menu
 * Special symbols::		Greek letters and other symbols
@@ -8867,7 +8871,7 @@ La@TeX{}, see the variable @code{org-entities} for the complete list.
 @samp{...} are all converted into special commands creating hyphens of
 different lengths or a compact set of dots.
 
-If you would like to see entities displayed as utf8 characters, use the
+If you would like to see entities displayed as UTF8 characters, use the
 following command@footnote{You can turn this on by default by setting the
 variable @code{org-pretty-entities}, or on a per-file base with the
 @code{#+STARTUP} option @code{entitiespretty}.}:
@@ -8908,6 +8912,9 @@ convention, or use, on a per-file basis:
 #+OPTIONS: ^:@{@}
 @end example
 
+@noindent With this setting, @samp{a_b} will not be interpreted as a
+subscript, but @samp{a_@{b@}} will.
+
 @table @kbd
 @kindex C-c C-x \
 @item C-c C-x \
@@ -8920,31 +8927,31 @@ format sub- and superscripts in a WYSIWYM way.
 @cindex La@TeX{} fragments
 
 @vindex org-format-latex-header
-With symbols, sub- and superscripts, HTML is pretty much at its end when
+Going beyond symbols and sub- and superscripts, a full formula language is
-it comes to representing mathematical formulas@footnote{Yes, there is
+needed.  Org-mode can contain La@TeX{} math fragments, and it supports ways
-MathML, but that is not yet fully supported by many browsers, and there
+to process these for several export backends.  When exporting to La@TeX{},
-is no decent converter for turning La@TeX{} or ASCII representations of
+the code is obviously left as it is.  When exporting to HTML, Org invokes the
-formulas into MathML. So for the time being, converting formulas into
+@uref{http://www.mathjax.org, MathJax library} (@pxref{Math formatting in
-images seems the way to go.}. More complex expressions need a dedicated
+HTML export}) to process and display the math@footnote{If you plan to use
-formula processor. To this end, Org-mode can contain arbitrary La@TeX{}
+this regularly or on pages with significant page views, you should install
-fragments. It provides commands to preview the typeset result of these
+@file{MathJax} on your own server in order to limit the load of our server.}.
-fragments, and upon export to HTML, all fragments will be converted to
+Finally, it can also process the mathematical expressions into
-images and inlined into the HTML document@footnote{The La@TeX{} export
+images@footnote{For this to work you need to be on a system with a working
-will not use images for displaying La@TeX{} fragments but include these
+La@TeX{} installation. You also need the @file{dvipng} program, available at
-fragments directly into the La@TeX{} code.}. For this to work you
+@url{http://sourceforge.net/projects/dvipng/}.  The La@TeX{} header that will
-need to be on a system with a working La@TeX{} installation. You also
+be used when processing a fragment can be configured with the variable
-need the @file{dvipng} program, available at
+@code{org-format-latex-header}.}  that can be displayed in a browser or in
-@url{http://sourceforge.net/projects/dvipng/}. The La@TeX{} header that
+DocBook documents.
-will be used when processing a fragment can be configured with the
-variable @code{org-format-latex-header}.
 
 La@TeX{} fragments don't need any special marking at all.  The following
 snippets will be identified as La@TeX{} source code:
 @itemize @bullet
 @item
-Environments of any kind.  The only requirement is that the
+Environments of any kind@footnote{When @file{MathJax} is used, only the
-@code{\begin} statement appears on a new line, preceded by only
+environment recognized by @file{MathJax} will be processed.  When dvipng is
-whitespace.
+used to create images, any La@TeX{} environments will be handled.}.  The only
+requirement is that the @code{\begin} statement appears on a new line,
+preceded by only whitespace.
 @item
 Text within the usual La@TeX{} math delimiters.  To avoid conflicts with
 currency specifications, single @samp{$} characters are only recognized as
@@ -8972,12 +8979,26 @@ If you need any of the delimiter ASCII sequences for other purposes, you
 can configure the option @code{org-format-latex-options} to deselect the
 ones you do not wish to have interpreted by the La@TeX{} converter.
 
+@vindex org-export-with-LaTeX-fragments
+LaTeX processing can be configured with the variable
+@code{org-export-with-LaTeX-fragments}.  The default setting is @code{t}
+which means @file{MathJax} for HTML, and no processing for DocBook, ASCII and
+LaTeX backends.  You can also set this variable on a per-file basis using one
+of these lines:
+
+@example
+#+OPTIONS: LaTeX:t          @r{Do the right thing automatically (MathJax)}
+#+OPTIONS: LaTeX:dvipng     @r{Force using dvipng images}
+#+OPTIONS: LaTeX:nil        @r{Do not process La@TeX{} fragments at all}
+#+OPTIONS: LaTeX:verbatim   @r{Verbatim export, for jsMath or so}
+@end example
+
 @node Previewing LaTeX fragments, CDLaTeX mode, LaTeX fragments, Embedded LaTeX
 @subsection Previewing LaTeX fragments
 @cindex LaTeX fragments, preview
 
-La@TeX{} fragments can be processed to produce preview images of the
+If you have @file{dvipng} installed, La@TeX{} fragments can be processed to
-typeset expressions:
+produce preview images of the typeset expressions:
 
 @table @kbd
 @kindex C-c C-x C-l
@@ -8999,14 +9020,6 @@ some aspects of the preview. In particular, the @code{:scale} (and for HTML
 export, @code{:html-scale}) property can be used to adjust the size of the
 preview images.
 
-During HTML export (@pxref{HTML export}), all La@TeX{} fragments are
-converted into images and inlined into the document if the following
-setting is active:
-
-@lisp
-(setq org-export-with-LaTeX-fragments t)
-@end lisp
-
 @node CDLaTeX mode,  , Previewing LaTeX fragments, Embedded LaTeX
 @subsection Using CDLa@TeX{} to enter math
 @cindex CDLa@TeX{}
@@ -9224,7 +9237,7 @@ tags:      @r{turn on/off inclusion of tags, may also be @code{not-in-toc}}
 <:         @r{turn on/off inclusion of any time/date stamps like DEADLINES}
 *:         @r{turn on/off emphasized text (bold, italic, underlined)}
 TeX:       @r{turn on/off simple @TeX{} macros in plain text}
-LaTeX:     @r{turn on/off La@TeX{} fragments}
+LaTeX:     @r{configure export of La@TeX{} fragments.  Default @code{auto}}
 skip:      @r{turn on/off skipping the text before the first heading}
 author:    @r{turn on/off inclusion of author name/email into exported file}
 email:     @r{turn on/off inclusion of author email into exported file}
@@ -9357,6 +9370,7 @@ language, but with additional support for tables.
 * Links in HTML export::	How links will be interpreted and formatted
 * Tables in HTML export::	How to modify the formatting of tables
 * Images in HTML export::	How to insert figures into HTML output
+* Math formatting in HTML export::  Beautiful math also on the web
 * Text areas in HTML export::	An alternative way to show an example
 * CSS support::			Changing the appearance of the output
 * JavaScript support::		Info and Folding in a web browser
@@ -9492,7 +9506,7 @@ tables, place something like the following before the table:
 #+ATTR_HTML: border="2" rules="all" frame="all"
 @end example
 
-@node Images in HTML export, Text areas in HTML export, Tables in HTML export, HTML export
+@node Images in HTML export, Math formatting in HTML export, Tables in HTML export, HTML export
 @subsection Images in HTML export
 
 @cindex images, inline in HTML
@@ -9529,7 +9543,41 @@ support text viewers and accessibility, and align it to the right.
 @noindent
 and you could use @code{http} addresses just as well.
 
-@node Text areas in HTML export, CSS support, Images in HTML export, HTML export
+@node Math formatting in HTML export, Text areas in HTML export, Images in HTML export, HTML export
+@subsection Math formatting in HTML export
+@cindex MathJax
+@cindex dvipng
+
+La@TeX{} math snippets (@pxref{LaTeX fragments}) can be displayed in two
+different ways on HTML pages.  The default is to use the
+@uref{http://www.mathjax.org, MathJax system} which should work out of the
+box with Org mode installation because @code{http://orgmode.org} serves
+@file{MathJax} for Org-mode users for small applications and for testing
+purposes.  @b{If you plan to use this regularly or on pages with significant
+page views, you should install MathJax on your own server in order to limit
+the load of our server.}  To configure @file{MathJax}, use the variable
+@code{org-export-html-mathjax-options} or insert something like the following
+into the buffer:
+
+@example
+#+MATHJAX: align:"left" mathml:t path:"/MathJax/MathJax.js"
+@end example
+
+@noindent See the docstring of the variable
+@code{org-export-html-mathjax-options} for the meaning of the parameters in
+this line.
+
+If you prefer, you can also request that La@TeX{} are processed into small
+images that will be inserted into the browser page.  Before the availability
+of MathJax, this was the default method for Org files.  This method requires
+that the @file{dvipng} program is available on your system.  You can still
+get this processing with
+
+@example
+#+OPTIONS: LaTeX:dvipng
+@end example
+
+@node Text areas in HTML export, CSS support, Math formatting in HTML export, HTML export
 @subsection Text areas in HTML export
 
 @cindex text areas, in HTML
@@ -11451,14 +11499,14 @@ The following header arguments are defined:
 * results::			Specify the type of results and how they will
                                 be collected and handled
 * file::			Specify a path for file output
-* dir::	                        Specify the default (possibly remote)
+* dir::				Specify the default (possibly remote)
                                 directory for code block execution
 * exports::			Export code and/or results
 * tangle::			Toggle tangling and specify file name
+* comments::			Toggle insertion of comments in tangled
+                                code files
 * no-expand::			Turn off variable assignment and noweb
                                 expansion during tangling
-* comments::                    Toggle insertion of comments in tangled
-                                code files
 * session::			Preserve the state of code evaluation
 * noweb::			Toggle expansion of noweb references
 * cache::			Avoid re-evaluating unchanged code blocks
@@ -11466,7 +11514,7 @@ The following header arguments are defined:
 * colnames::			Handle column names in tables
 * rownames::			Handle row names in tables
 * shebang::			Make tangled files executable
-* eval::                        Limit evaluation of specific code blocks
+* eval::			Limit evaluation of specific code blocks
 @end menu
 
 @node var, results, Specific header arguments, Specific header arguments
@@ -12094,7 +12142,7 @@ Setting the @code{:shebang} header argument to a string value
 first line of any tangled file holding the code block, and the file
 permissions of the tangled file are set to make it executable.
 
-@node eval, , shebang, Specific header arguments
+@node eval,  , shebang, Specific header arguments
 @subsubsection @code{:eval}
 The @code{:eval} header argument can be used to limit the evaluation of
 specific code blocks.  @code{:eval} accepts two arguments ``never'' and

lisp/org-exp.el

@@ -471,20 +471,34 @@ This option can also be set with the +OPTIONS line, e.g. \"TeX:nil\"."
   :group 'org-export-latex
   :type 'boolean)
 
-(defcustom org-export-with-LaTeX-fragments nil
+(defcustom org-export-with-LaTeX-fragments t
-  "Non-nil means convert LaTeX fragments to images when exporting to HTML.
+  "Non-nil means process LaTeX math fragments for HTML display.
-When set, the exporter will find LaTeX environments if the \\begin line is
+When set, the exporter will find and process LaTeX environments if the
-the first non-white thing on a line.  It will also find the math delimiters
+\\begin line is the first non-white thing on a line.  It will also find
-like $a=b$ and \\( a=b \\) for inline math,  $$a=b$$ and \\[ a=b \\] for
+and process  the math delimiters like $a=b$ and \\( a=b \\) for inline math,
-display math.
+$$a=b$$ and \\[ a=b \\] for display math.
 
-This option can also be set with the +OPTIONS line, e.g. \"LaTeX:t\".
+This option can also be set with the +OPTIONS line, e.g. \"LaTeX:mathjax\".
+
+Allowed values are:
+
+nil        Don't do anything.
+verbatim   Keep eveything in verbatim
+dvipng     Process the LaTeX fragments to images.
+           This will also include processing of non-math environments.
+t          Do MathJax preprocessing if there is at least on math snippet,
+           and arrange for MathJax.js to be loaded.
 
 The default is nil, because this option needs the `dvipng' program which
 is not available on all systems."
   :group 'org-export-translation
   :group 'org-export-latex
-  :type 'boolean)
+  :type '(choice
+	  (const :tag "Do not process math in any way" nil)
+	  (const :tag "Obsolete, use dvipng setting" t)
+	  (const :tag "Use dvipng to make images" dvipng)
+	  (const :tag "Use MathJax to display math" mathjax)
+	  (const :tag "Leave math verbatim" verbatim)))
 
 (defcustom org-export-with-fixed-width t
   "Non-nil means lines starting with \":\" will be in fixed width font.
@@ -675,12 +689,13 @@ modified) list.")
       (let ((re (org-make-options-regexp
 		 (append
 		  '("TITLE" "AUTHOR" "DATE" "EMAIL" "TEXT" "OPTIONS" "LANGUAGE"
+		    "MATHJAX"
 		    "LINK_UP" "LINK_HOME" "SETUPFILE" "STYLE"
 		    "LATEX_HEADER" "LATEX_CLASS"
 		    "EXPORT_SELECT_TAGS" "EXPORT_EXCLUDE_TAGS"
 		    "KEYWORDS" "DESCRIPTION" "MACRO" "BIND" "XSLT")
 		  (mapcar 'car org-export-inbuffer-options-extra))))
-	    p key val text options a pr style
+	    p key val text options mathjax a pr style
 	    latex-header latex-class macros letbind
 	    ext-setup-or-nil setup-contents (start 0))
 	(while (or (and ext-setup-or-nil
@@ -712,6 +727,8 @@ modified) list.")
 	    (setq text (if text (concat text "\n" val) val)))
 	   ((string-equal key "OPTIONS")
 	    (setq options (concat val " " options)))
+	   ((string-equal key "MATHJAX")
+	    (setq mathjax (concat val " " mathjax)))
 	   ((string-equal key "BIND")
 	    (push (read (concat "(" val ")")) letbind))
 	   ((string-equal key "XSLT")
@@ -748,6 +765,8 @@ modified) list.")
 	  (setq p (plist-put p :latex-class latex-class)))
 	(when options
 	  (setq p (org-export-add-options-to-plist p options)))
+	(when mathjax
+	  (setq p (plist-put p :mathjax mathjax)))
 	;; Add macro definitions
 	(setq p (plist-put p :macro-date "(eval (format-time-string \"$1\"))"))
 	(setq p (plist-put p :macro-time "(eval (format-time-string \"$1\"))"))

lisp/org-html.el

@@ -209,6 +209,112 @@ settings with <style>...</style> tags."
 ;;;###autoload
 (put 'org-export-html-style-extra 'safe-local-variable 'stringp)
 
+(defcustom org-export-html-mathjax-options
+  '((path  "http://orgmode.org/mathjax/MathJax.js")
+    (scale "100")
+    (align "center")
+    (indent "2em")
+    (mathml nil))
+  "Options for MathJax setup.
+
+path        The path where to find MathJax
+scale       Scaling for the HTML-CSS backend, usually between 100 and 133
+align       How to align display math: left, center, or right
+indent      If align is not center, how far from the left/right side?
+mathml      Should a MathML player be used if available?
+            This is faster and reduces bandwidth use, but currently
+            sometimes has lower spacing quality.  Therefore, the default is
+            nil.  When browsers get better, this switch can be flipped.
+
+You can also customize this for each buffer, using something like
+
+#+MATHJAX: scale:\"133\" align:\"right\" mathml:t path:\"/MathJax/\""
+  :group 'org-export-html
+  :type '(list :greedy t
+	      (list :tag "path   (the path from where to load MathJax.js)"
+		    (const :format "       " path) (string))
+	      (list :tag "scale  (scaling for the displayed math)"
+		    (const :format "       " scale) (string))
+	      (list :tag "align  (alignment of displayed equations)"
+		    (const :format "       " align) (string))
+	      (list :tag "indent (indentation with left or right alignment)"
+		    (const :format "       " indent) (string))
+	      (list :tag "mathml (should MathML display be used is possible)"
+		    (const :format "       " mathml) (boolean))))
+
+(defun org-export-html-mathjax-config (template options in-buffer)
+  "Insert the user setup into the matchjax template."
+  (let (name val (yes "   ") (no "// ") x)
+    (mapc
+     (lambda (e)
+       (setq name (car e) val (nth 1 e))
+       (if (string-match (concat "\\<" (symbol-name name) ":") in-buffer)
+	   (setq val (car (read-from-string
+			   (substring in-buffer (match-end 0))))))
+       (if (not (stringp val)) (setq val (format "%s" val)))
+       (if (string-match (concat "%" (upcase (symbol-name name))) template)
+	   (setq template (replace-match val t t template))))
+     options)
+    (setq val (nth 1 (assq 'mathml options)))
+    (if (string-match (concat "\\<mathml:") in-buffer)
+	(setq val (car (read-from-string
+			(substring in-buffer (match-end 0))))))
+    ;; Exchange prefixes depending on mathml setting
+    (if (not val) (setq x yes yes no no x))
+    ;; Replace cookies to turn on or off the config/jax lines
+    (if (string-match ":MMLYES:" template)
+	(setq template (replace-match yes t t template)))
+    (if (string-match ":MMLNO:" template)
+	(setq template (replace-match no t t template)))
+    ;; Return the modified template
+    template))
+
+(defcustom org-export-html-mathjax-template
+  "<script type=\"text/javascript\" src=\"%PATH\">
+<!--/*--><![CDATA[/*><!--*/
+    MathJax.Hub.Config({
+        // Only one of the two following lines, depending on user settings
+        // First allows browser-native MathML display, second forces HTML/CSS
+        :MMLYES: config: [\"MMLorHTML.js\"], jax: [\"input/TeX\"],
+        :MMLNO: jax: [\"input/TeX\", \"output/HTML-CSS\"],
+        extensions: [\"tex2jax.js\",\"TeX/AMSmath.js\",\"TeX/AMSsymbols.js\",
+                     \"TeX/noUndefined.js\"],
+        tex2jax: {
+            inlineMath: [ [\"\\\\(\",\"\\\\)\"] ],
+            displayMath: [ ['$$','$$'], [\"\\\\[\",\"\\\\]\"] ],
+            skipTags: [\"script\",\"noscript\",\"style\",\"textarea\",\"pre\",\"code\"],
+            ignoreClass: \"tex2jax_ignore\",
+            processEscapes: false,
+            processEnvironments: true,
+            preview: \"TeX\"
+        },
+        showProcessingMessages: true,
+        displayAlign: \"%ALIGN\",
+        displayIndent: \"%INDENT\",
+
+        \"HTML-CSS\": {
+             scale: %SCALE,
+             availableFonts: [\"STIX\",\"TeX\"],
+             preferredFont: \"TeX\",
+             webFont: \"TeX\",
+             imageFont: \"TeX\",
+             showMathMenu: true,
+        },
+        MMLorHTML: {
+             prefer: {
+                 MSIE:    \"MML\",
+                 Firefox: \"MML\",
+                 Opera:   \"HTML\",
+                 other:   \"HTML\"
+             }
+        }
+    });
+/*]]>*///-->
+</script>"
+  "The MathJax setup for XHTML files."
+  :group 'org-export-html
+  :type 'string)
+
 (defcustom org-export-html-tag-class-prefix ""
   "Prefix to class names for TODO keywords.
 Each tag gets a class given by the tag itself, with this prefix.
@@ -439,7 +545,13 @@ This may also be a function, building and inserting the postamble.")
 			(file-name-nondirectory
 			 org-current-export-file)))
      org-current-export-dir nil "Creating LaTeX image %s"
-     nil nil (eq (plist-get parameters :LaTeX-fragments) 'verbatim)))
+     nil nil
+     (cond
+      ((eq (plist-get parameters :LaTeX-fragments) 'verbatim) 'verbatim)
+      ((eq (plist-get parameters :LaTeX-fragments) 'mathjax ) 'mathjax)
+      ((eq (plist-get parameters :LaTeX-fragments) t        ) 'mathjax)
+      ((eq (plist-get parameters :LaTeX-fragments) 'dvipng  ) 'dvipng)
+      (t nil))))
   (goto-char (point-min))
   (let (label l1)
     (while (re-search-forward "\\\\ref{\\([^{}\n]+\\)}" nil t)
@@ -812,6 +924,7 @@ PUB-DIR is set, use this as the publishing directory."
 	  (buffer-substring
 	   (if region-p (region-beginning) (point-min))
 	   (if region-p (region-end) (point-max))))
+	 (org-export-have-math nil)
 	 (lines
 	  (org-split-string
 	   (org-export-preprocess-string
@@ -835,6 +948,16 @@ PUB-DIR is set, use this as the publishing directory."
 	    :LaTeX-fragments
 	    (plist-get opt-plist :LaTeX-fragments))
 	   "[\r\n]"))
+	 (mathjax
+	  (if (or (eq (plist-get opt-plist :LaTeX-fragments) 'mathjax)
+		  (and org-export-have-math
+		       (eq (plist-get opt-plist :LaTeX-fragments) t)))
+
+	      (org-export-html-mathjax-config
+	       org-export-html-mathjax-template
+	       org-export-html-mathjax-options
+	       (or (plist-get opt-plist :mathjax) ""))
+	    ""))
 	 table-open type
 	 table-buffer table-orig-buffer
 	 ind item-type starter didclose
@@ -904,6 +1027,7 @@ lang=\"%s\" xml:lang=\"%s\">
 <meta name=\"description\" content=\"%s\"/>
 <meta name=\"keywords\" content=\"%s\"/>
 %s
+%s
 </head>
 <body>
 <div id=\"content\">
@@ -922,6 +1046,7 @@ lang=\"%s\" xml:lang=\"%s\">
 		 (or charset "iso-8859-1")
 		 date author description keywords
 		 style
+		 mathjax
 		 (if (or link-up link-home)
 		     (concat
 		      (format org-export-html-home/up-format

lisp/org.el

@@ -15880,7 +15880,7 @@ The images can be removed again with \\[org-ctrl-c-ctrl-c]."
 	 (concat "ltxpng/" (file-name-sans-extension
 			    (file-name-nondirectory
 			     buffer-file-name)))
-	 default-directory 'overlays msg at 'forbuffer)
+	 default-directory 'overlays msg at 'forbuffer 'dvipng)
       (message msg "done.  Use `C-c C-c' to remove images.")))))
 
 (defvar org-latex-regexps
@@ -15894,8 +15894,9 @@ The images can be removed again with \\[org-ctrl-c-ctrl-c]."
     ("$$" "\\$\\$[^\000]*?\\$\\$" 0 nil))
   "Regular expressions for matching embedded LaTeX.")
 
+(defvar org-export-have-math nil) ;; dynamic scoping
 (defun org-format-latex (prefix &optional dir overlays msg at
-				forbuffer protect-only)
+				forbuffer processing-type)
   "Replace LaTeX fragments with links to an image, and produce images.
 Some of the options can be changed using the variable
 `org-format-latex-options'."
@@ -15909,7 +15910,7 @@ Some of the options can be changed using the variable
 	 (org-format-latex-header-extra
 	  (plist-get (org-infile-export-plist) :latex-header-extra))
 	 (cnt 0) txt hash link beg end re e checkdir
-	 executables-checked
+	 executables-checked string
 	 m n block linkfile movefile ov)
     ;; Check the different regular expressions
     (while (setq e (pop re-list))
@@ -15925,9 +15926,26 @@ Some of the options can be changed using the variable
 			 (not (eq (get-char-property (match-beginning n)
 						     'org-overlay-type)
 				  'org-latex-overlay))))
-	    (if protect-only
+	    (setq org-export-have-math t)
+	    (cond
+	     ((eq processing-type 'verbatim)
+	      ;; Leave the text verbatim, just protect it
+	      (add-text-properties (match-beginning n) (match-end n)
+				   '(org-protected t)))
+	     ((eq processing-type 'mathjax)
+	      ;; Prepare for MathJax processing
+	      (setq string (match-string n))
+	      (if (equal m "$")
+		  (save-excursion
+		    (delete-region (match-beginning n) (match-end n))
+		    (goto-char (match-beginning n))
+		    (insert (org-add-props (concat "\\(" (substring string 1 -1)
+						   "\\)")
+				'(org-protected t))))
 		(add-text-properties (match-beginning n) (match-end n)
-				     '(org-protected t))
+				     '(org-protected t))))
+	     ((or (eq processing-type 'dvipng) t)
+	      ;; Process to an image
 	      (setq txt (match-string n)
 		    beg (match-beginning n) end (match-end n)
 		    cnt (1+ cnt))
@@ -15981,7 +15999,8 @@ Some of the options can be changed using the variable
 		(delete-region beg end)
 		(insert (org-add-props link
 			    (list 'org-latex-src
-				  (replace-regexp-in-string "\"" "" txt))))))))))))
+				  (replace-regexp-in-string
+				   "\"" "" txt)))))))))))))
 
 ;; This function borrows from Ganesh Swami's latex2png.el
 (defun org-create-formula-image (string tofile options buffer)
@@ -17650,14 +17669,6 @@ See the individual commands for more information."
       (org-inside-LaTeX-fragment-p)]
      ["Insert citation" org-reftex-citation t]
      "--"
-     ["Export LaTeX fragments as images"
-      (if (featurep 'org-exp)
-	  (setq org-export-with-LaTeX-fragments
-		(not org-export-with-LaTeX-fragments))
-	(require 'org-exp))
-      :style toggle :selected (and (boundp 'org-export-with-LaTeX-fragments)
-				   org-export-with-LaTeX-fragments)]
-     "--"
      ["Template for BEAMER" org-insert-beamer-options-template t])
     "--"
     ("MobileOrg"