Update for leanpub preview

manuscript/extras/javascript/auto-expand-nav.js

@@ -0,0 +1,27 @@
+document.addEventListener("DOMContentLoaded", function() {
+    load_navpane();
+});
+
+function load_navpane() {
+    var width = window.innerWidth;
+    if (width <= 1200) {
+        return;
+    }
+
+    var nav = document.getElementsByClassName("md-nav");
+    for(var i = 0; i < nav.length; i++) {
+        if (typeof nav.item(i).style === "undefined") {
+            continue;
+        }
+
+        if (nav.item(i).getAttribute("data-md-level") && nav.item(i).getAttribute("data-md-component")) {
+            nav.item(i).style.display = 'block';
+            nav.item(i).style.overflow = 'visible';
+        }
+    }
+
+    var nav = document.getElementsByClassName("md-nav__toggle");
+    for(var i = 0; i < nav.length; i++) {
+       nav.item(i).checked = true;
+    }
+}