Valid JSON doesn't support single quoted strings.

README.mkdn

@@ -59,11 +59,11 @@ Springy 1.2+ also accepts JSON, see
 [demo-json.html](http://dhotson.github.com/springy/demo-json.html):
 
     graphJSON = {
-      "nodes": ['mark', 'higgs', 'other', 'etc'],
+      "nodes": ["mark", "higgs", "other", "etc"],
       "edges": [
-        ['mark', 'higgs'],
-        ['mark', 'etc'],
-        ['mark', 'other']
+        ["mark", "higgs"],
+        ["mark", "etc"],
+        ["mark", "other"]
       ]
     };
 

demo-json.html

@@ -8,16 +8,16 @@
 <script>
 var graphJSON = {
   "nodes": [
-    'Amphitryon',
-    'Alcmene',
-    'Iphicles',
-    'Heracles'
+    "Amphitryon",
+    "Alcmene",
+    "Iphicles",
+    "Heracles"
   ],
   "edges": [
-    ['Amphitryon', 'Alcmene'],
-    ['Alcmene', 'Amphitryon'],
-    ['Amphitryon', 'Iphicles'],
-    ['Amphitryon', 'Heracles']
+    ["Amphitryon", "Alcmene"],
+    ["Alcmene", "Amphitryon"],
+    ["Amphitryon", "Iphicles"],
+    ["Amphitryon", "Heracles"]
   ]
 };