1 files changed, 143 insertions, 0 deletions
diff --git a/_includes/scripts/lib/lazyload.js b/_includes/scripts/lib/lazyload.js
new file mode 100644
index 0000000..9911535
--- /dev/null
+++ b/_includes/scripts/lib/lazyload.js
@@ -0,0 +1,143 @@
+(function() {
+  var Set = (function() {
+    var add = function(item) {
+      var i, data = this._data;
+      for (i = 0; i < data.length; i++) {
+        if (data[i] === item) {
+          return;
+        }
+      }
+      this.size ++;
+      data.push(item);
+      return data;
+    };
+
+    var Set = function(data) {
+      this.size = 0;
+      this._data = [];
+      var i;
+      if (data.length > 0) {
+        for (i = 0; i < data.length; i++) {
+          add.call(this, data[i]);
+        }
+      }
+    };
+    Set.prototype.add = add;
+    Set.prototype.get = function(index) { return this._data[index]; };
+    Set.prototype.has = function(item) {
+      var i, data = this._data;
+      for (i = 0; i < data.length; i++) {
+        if (this.get(i) === item) {
+          return true;
+        }
+      }
+      return false;
+    };
+    Set.prototype.is = function(map) {
+      if (map._data.length !== this._data.length) { return false; }
+      var i, j, flag, tData = this._data, mData = map._data;
+      for (i = 0; i < tData.length; i++) {
+        for (flag = false, j = 0; j < mData.length; j++) {
+          if (tData[i] === mData[j]) {
+            flag = true;
+            break;
+          }
+        }
+        if (!flag) { return false; }
+      }
+      return true;
+    };
+    Set.prototype.values = function() {
+      return this._data;
+    };
+    return Set;
+  })();
+
+  window.Lazyload = (function(doc) {
+    var queue = {js: [], css: []}, sources = {js: {}, css: {}}, context = this;
+    var createNode = function(name, attrs) {
+      var node = doc.createElement(name), attr;
+      for (attr in attrs) {
+        if (attrs.hasOwnProperty(attr)) {
+          node.setAttribute(attr, attrs[attr]);
+        }
+      }
+      return node;
+    };
+    var end = function(type, url) {
+      var s, q, qi, cbs, i, j, cur, val, flag;
+      if (type === 'js' || type ==='css') {
+        s = sources[type], q = queue[type];
+        s[url] = true;
+        for (i = 0; i < q.length; i++) {
+          cur = q[i];
+          if (cur.urls.has(url)) {
+            qi = cur, val = qi.urls.values();
+            qi && (cbs = qi.callbacks);
+            for (flag = true, j = 0; j < val.length; j++) {
+              cur = val[j];
+              if (!s[cur]) {
+                flag = false;
+              }
+            }
+            if (flag && cbs && cbs.length > 0) {
+              for (j = 0; j < cbs.length; j++) {
+                cbs[j].call(context);
+              }
+              qi.load = true;
+            }
+          }
+        }
+      }
+    };
+    var load = function(type, urls, callback) {
+      var s, q, qi, node, i, cur,
+        _urls = typeof urls === 'string' ? new Set([urls]) : new Set(urls), val, url;
+      if (type === 'js' || type ==='css') {
+        s = sources[type], q = queue[type];
+        for (i = 0; i < q.length; i++) {
+          cur = q[i];
+          if (_urls.is(cur.urls)) {
+            qi = cur;
+            break;
+          }
+        }
+        val = _urls.values();
+        if (qi) {
+          callback && (qi.load || qi.callbacks.push(callback));
+          callback && (qi.load && callback());
+        } else {
+          q.push({
+            urls: _urls,
+            callbacks: callback ? [callback] : [],
+            load: false
+          });
+          for (i = 0; i < val.length; i++) {
+            node = null, url = val[i];
+            if (s[url] === undefined) {
+              (type === 'js' ) && (node = createNode('script', { src: url }));
+              (type === 'css') && (node = createNode('link', { rel: 'stylesheet', href: url }));
+              if (node) {
+                node.onload = (function(type, url) {
+                  return function() {
+                    end(type, url);
+                  };
+                })(type, url);
+                (doc.head || doc.body).appendChild(node);
+                s[url] = false;
+              }
+            }
+          }
+        }
+      }
+    };
+    return {
+      js: function(url, callback) {
+        load('js', url, callback);
+      },
+      css: function(url, callback) {
+        load('css', url, callback);
+      }
+    };
+  })(this.document);
+})();