more reliable seeded shuffle for lists

_includes/head.html

@@ -714,4 +714,30 @@
       // Avaz, WeaveChat, CBoard, Clicker, GoTalk Now Plus
     ];
   </script>
+  <script>
+    // https://stackoverflow.com/questions/16801687/javascript-random-ordering-with-seed
+    window.shuffle = function(array, seed) {                // <-- ADDED ARGUMENT
+    var m = array.length, t, i;
+
+    // While there remain elements to shuffle…
+    while (m) {
+
+      // Pick a remaining element…
+      i = Math.floor(random(seed) * m--);        // <-- MODIFIED LINE
+
+      // And swap it with the current element.
+      t = array[m];
+      array[m] = array[i];
+      array[i] = t;
+      ++seed                                     // <-- ADDED LINE
+    }
+
+    return array;
+  }
+
+  function random(seed) {
+    var x = Math.sin(seed++) * 10000; 
+    return x - Math.floor(x);
+  }
+  </script>
 </head>

certifications/index.md

@@ -112,7 +112,7 @@ bg: 3
   var apps = document.getElementById('apps_list');
   var other_apps = document.getElementById('other_apps_list');
   var app_template = apps.querySelectorAll('.caption')[0];
-  var list = [].concat(window.app_list || []);
+  var list = window.shuffle(window.app_list || [], (new Date()).getDate());
   if(list.length == 0) {
     list.push({name: "None available", desc: " ", rank: 1});
   }

index.html

@@ -331,7 +331,7 @@ <h2>Get Involved!
 <script>
   var apps = document.getElementById('apps_list');
   var app_template = apps.querySelectorAll('.caption')[0];
-  var list = [].concat(window.app_list || []);
+  var list = window.shuffle(window.app_list || [], (new Date()).getDate());
   if(list.length == 0) {
     list.push({name: "None available", desc: " ", rank: 1});
   }

vocabularies/index.md

@@ -282,6 +282,7 @@ abrupt, accept, hope, wish, meal, comply
       list.push({name: "None available", desc: " ", rank: 1});
     }
     var day = (new Date()).getDate();
+    list = window.shuffle(list, day);
     var start_num = (day / 31) - 0.5;
     if(day % 2 == 0) { start_num = start_num * -1; }
     list.forEach(function(item) {