Issue 133: Add lazy loading for images support

indefero/www/media/idf/js/logo.cache.js

@@ -0,0 +1,46 @@
+$(function () {
+    var logoCache = {};
+    var waiting = 0;
+    function logoUpdate() {
+        if (waiting == 0) {
+            $(".logo").each(function () {
+                var self = $(this);
+                var logo = $(this).data("logo");
+                if (logo == "") {
+                    logo = undefined;
+                }
+                self.attr("src", logoCache[logo]);
+            });
+        } else {
+            waiting -= 1;
+        }
+    }
+    $(".logo").each(function () {
+        var logoSrc = $(this).data("src");
+        var logo = $(this).data("logo");
+        var self = $(this);
+        if (!logoSrc) {
+            return;
+        }
+
+        if (logo == "") {
+            logo = undefined;
+        }
+
+        if (!(logo in logoCache)) {
+            logoCache[logo] = logoSrc;
+        }
+    });
+
+    waiting = Object.keys(logoCache).length - 1;
+    $.each(logoCache, function (index, element) {
+        $.ajax({
+            url: logoCache[index],
+            success: function(data) {
+                logoCache[index] = data;
+                logoUpdate();
+            },
+            async: true
+        });
+    });
+});