Merge branch 'issue576' into develop. Issue mathjax#576.

Author: dpvc

unpacked/extensions/MatchWebFonts.js

@@ -28,7 +28,7 @@
  */
 
 (function (HUB,AJAX) {
-  var VERSION = "2.3";
+  var VERSION = "2.3.1";
 
   var CONFIG = MathJax.Hub.CombineConfig("MatchWebFonts",{
     matchFor: {
@@ -98,9 +98,10 @@
         //
         //  Remove markers
         //
+        scripts = scripts.concat(size);  // some scripts have been moved to the size array
         for (i = 0, m = scripts.length; i < m; i++) {
           script = scripts[i];
-          if (script.parentNode && script.MathJax.elementJax) {
+          if (script && script.parentNode && script.MathJax.elementJax) {
             script.parentNode.removeChild(script.previousSibling);
           }
         }
@@ -164,6 +165,7 @@
         //
         //  Remove markers
         //
+        scripts = scripts.concat(size);  // some scripts have been moved to the size array
         for (i = 0, m = scripts.length; i < m; i++) {
           script = scripts[i];
           if (script.parentNode && script.MathJax.elementJax) {
@@ -303,7 +305,7 @@
     });
   });
 
-  HUB.Startup.signal.Post("MathWebFont Extension Ready");
+  HUB.Startup.signal.Post("MatchWebFonts Extension Ready");
   AJAX.loadComplete("[MathJax]/extensions/MatchWebFonts.js");
 
 })(MathJax.Hub,MathJax.Ajax);

unpacked/jax/output/HTML-CSS/jax.js

@@ -469,6 +469,23 @@
     //
     InitializeHTML: function () {
       this.PreloadWebFonts();
+      this.getDefaultExEm();
+      //
+      //  If the defaultEm size is zero, it might be that a web font hasn't
+      //  arrived yet, so try to wait for it, but don't wait too long.
+      //
+      if (this.defaultEm) return;
+      var ready = MathJax.Callback();
+      AJAX.timer.start(AJAX,function (check) {
+        if (check.time(ready)) {HUB.signal.Post("HTML-CSS Jax - no default em size"); return}
+        HTMLCSS.getDefaultExEm();
+        if (HTMLCSS.defaultEm) {ready()} else {setTimeout(check,check.delay)}
+      },this.defaultEmDelay,this.defaultEmTimeout);
+      return ready;
+    },
+    defaultEmDelay: 100,      // initial delay when checking for defaultEm
+    defaultEmTimeout: 1000,   // when to stop looking for defaultEm
+    getDefaultExEm: function () {
       //
       //  Get the default sizes (need styles in place to do this)
       //