diff --git a/lib/index.js b/lib/index.js
index 8d2deb0..e939579 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -3,16 +3,67 @@
   class Delegator {
     constructor (selector/* root选择器 */) {
       // TODO
+      this.root = document.querySelector(selector)
+      this.events = {}
+      this.delegator = e => {
+        var _event = e || window.event
+        var target = _event.target || _event.srcElement
+        var currentTarget = _event.currentTarget
+
+        var _events = this.events[e.type]
+
+        while (target !== currentTarget) {
+          _events.forEach(t => {
+            if (target.matches(t.selector)) {
+              var sTarget = target
+              t.callback.call(sTarget, e)
+            }
+          })
+
+          target = target.parentNode
+        }
+      }
     }
 
     on (event/* 绑定事件 */, selector/* 触发事件节点对应选择器 */, fn/* 出发函数 */) {
       // TODO
+      if (!Array.isArray(this.events[event])) {
+        this.events[event] = []
+      }
+
+      this.root.addEventListener(event, this.delegator, false)
+
+      this.events[event].push({
+        selector: selector,
+        callback: fn
+      })
+
+      return this
     }
 
     destroy () {
       // TODO
+      for (let type in this.events) {
+        this.root.removeEventListener(type, this.delegator, false);
+      }
     }
   }
 
+  // 处理 matches 的兼容性
+  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       
+      }
+  }
+
   root.Delegator = Delegator
 }(window, document)
\ No newline at end of file
diff --git a/package.json b/package.json
index 89e61a0..c61cfe3 100644
--- a/package.json
+++ b/package.json
@@ -1,29 +1,29 @@
 {
-    "name": "exercise20",
-    "version": "0.0.1",
-    "description": "test",
-    "main": "index.js",
-    "scripts": {
-      "test": "karma start"
-    },
-    "repository": {
-      "type": "git",
-      "url": "git+https://github.com/FE-star/exercise20.git"
-    },
-    "keywords": [
-      "test"
-    ],
-    "author": "Daniel Yang",
-    "license": "MIT",
-    "bugs": {
-      "url": "https://github.com/FE-star/exercise20/issues"
-    },
-    "homepage": "https://github.com/FE-star/exercise20#readme",
-    "devDependencies": {
-      "karma": "^1.7.0",
-      "karma-chrome-launcher": "^1.0.1",
-      "karma-mocha": "^1.3.0",
-      "mocha": "^3.5.0",
-      "should": "^11.2.1"
-    }
-}
\ No newline at end of file
+  "name": "exercise20",
+  "version": "0.0.1",
+  "description": "test",
+  "main": "index.js",
+  "scripts": {
+    "test": "karma start"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/FE-star/exercise20.git"
+  },
+  "keywords": [
+    "test"
+  ],
+  "author": "Daniel Yang",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/FE-star/exercise20/issues"
+  },
+  "homepage": "https://github.com/FE-star/exercise20#readme",
+  "devDependencies": {
+    "karma": "^1.7.0",
+    "karma-chrome-launcher": "^1.0.1",
+    "karma-mocha": "^1.3.0",
+    "mocha": "^3.5.0",
+    "should": "^11.2.1"
+  }
+}