sanitize the id name in the DOM

Author: expikr

src/theme/book.js

@@ -320,9 +320,9 @@ function playground_text(playground, hidden = true) {
         var theme;
         try { theme = localStorage.getItem('mdbook-theme'); } catch (e) { }
         if (theme === null || theme === undefined) {
-            return default_theme;
+            return default_theme.replace(/\W+/g, '_').toLowerCase();
         } else {
-            return theme;
+            return theme.replace(/\W+/g, '_').toLowerCase();
         }
     }
 
@@ -364,7 +364,7 @@ function playground_text(playground, hidden = true) {
         var previousTheme = get_theme().replace(/\W+/g, '_').toLowerCase();
         var selectedTheme =       theme.replace(/\W+/g, '_').toLowerCase();
         if (store) {
-            try { localStorage.setItem('mdbook-theme', theme); } catch (e) { }
+            try { localStorage.setItem('mdbook-theme', selectedTheme); } catch (e) { }
         }
 
         try { 
@@ -375,6 +375,9 @@ function playground_text(playground, hidden = true) {
         updateThemeSelected();
     }
 
+    // Sanitize theme id names
+    themePopup.querySelectorAll("button").forEach(e=>{e.id=e.id.replace(/\W+/g, '_').toLowerCase();});
+
     // Set theme
     var theme = get_theme();