diff --git a/lib/index.js b/lib/index.js
index 8d2deb0..870c36b 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -3,14 +3,53 @@
   class Delegator {
     constructor (selector/* root选择器 */) {
       // TODO
+      this.root = doc.querySelector(selector);
+      this.delegatedListeners = {};
+    }
+
+    delegator (eventNm) {
+      return (e, ...args) => {
+        var event = e || window.event;
+        // console.log(e);
+        var i = 0, len = event.path.length;
+        while (i < len) {
+          var target = event.path[i];
+          this.delegatedListeners[eventNm].listeners.forEach(item => {
+            if (target.matches(item.selector)) {
+              item.fn.call(target, e, ...args);
+            }
+          })
+          if (target === this.root) return
+          i++;
+        }
+      }
     }
 
     on (event/* 绑定事件 */, selector/* 触发事件节点对应选择器 */, fn/* 出发函数 */) {
-      // TODO
+      // 字符串处理selector
+      selector = selector.replace(/^\s+(.*?)\s+$/g, '$1');
+
+      if (!this.delegatedListeners[event]) {
+        let delegator = this.delegator(event);
+        this.delegatedListeners[event] = {
+          delegator,
+          listeners: []
+        }
+        this.root.addEventListener(event, delegator);
+      };
+      this.delegatedListeners[event].listeners.push({
+        selector,
+        fn
+      })
+
+      return this
     }
 
     destroy () {
       // TODO
+      Object.keys(this.delegatedListeners).forEach(eventNm => {
+          this.root.removeEventListener(eventNm, this.delegatedListeners[eventNm].delegator);
+      })
     }
   }
 
diff --git a/lib/polyfill.js b/lib/polyfill.js
new file mode 100644
index 0000000..3cc5a48
--- /dev/null
+++ b/lib/polyfill.js
@@ -0,0 +1,14 @@
+if (!Element.prototype.matches) {
+    Element.prototype.matches =
+        Element.prototype.matchesSelector ||
+        Element.prototype.mozMatchesSelector ||
+        Element.prototype.msMatchesSelector ||
+        Element.prototype.oMatchesSelector ||
+        Element.prototype.webkitMatchesSelector ||
+        function(s) {
+            var matches = (this.document || this.ownerDocument).querySelectorAll(s),
+            i = matches.length;
+            while (--i >= 0 && matches.item(i) !== this) {}
+            return i > -1;            
+    };
+}
\ No newline at end of file