>[warning]v-on綁定事件 **** 1. 思路, 還是解析標簽的屬性, 如果有v-on提取事件名字, 然后底層利用addEventListener綁定對應事件 代碼如下: ~~~ <script> Compile.prototype = { nodeToFragment(el) { let fragment = document.createDocumentFragment(); let child = el.firstChild; while (child) { fragment.appendChild(child); child = el.firstChild; } return fragment; }, compileElement(el) { let childNodes = el.childNodes; let self = this; [].slice.call(childNodes).forEach(function (node) { let reg = /\{\{(.*)\}\}/; let text = node.textContent; if (self.isElementNode(node)) { self.compile(node); } else if (self.isTextNode(node) && reg.test(text)) { self.compileText(node, reg.exec(text)[1]); } if (node.childNodes && node.childNodes.length) { self.compileElement(node); } }) }, compileText(node, exp) { let self = this; let initText = this.vm[exp]; self.updateText(node, initText); new Watcher(this.vm, function (val) { self.updateText(node, val); }, exp); }, updateText(node, value) { node.textContent = typeof value === 'undefined' ? '' : value; }, isTextNode: function (node) { return node.nodeType == 3; }, isElementNode: function (node) { return node.nodeType == 1; }, compile(node) { let nodeAttrs = node.attributes; let self = this; Array.prototype.forEach.call(nodeAttrs, function (attr) { let attrName = attr.name; if (self.isDirective(attrName)) { let exp = attr.value; let dir = attrName.substring(2); // 4. 判斷是否是事件指令 if (self.isEventDirective(dir)) { // 6. 給事件進行解析 self.compileEvent(node, self.vm, exp, dir); } else if (self.isModelDirective(dir)) { self.compileModel(node, self.vm, exp); } node.removeAttribute(attrName); } }); }, isDirective: function (attr) { return attr.indexOf('v-') == 0; }, isModelDirective: function (dir) { return dir.indexOf('model') === 0; }, compileModel: function (node, vm, exp) { let self = this; let val = this.vm[exp]; this.modelUpdater(node, val); new Watcher(this.vm, function (value) { self.modelUpdater(node, value); }, exp); node.addEventListener('input', function (e) { let newValue = e.target.value; if (val === newValue) { return; } self.vm[exp] = newValue; val = newValue; }); }, modelUpdater: function (node, value) { node.value = typeof value == 'undefined' ? '' : value; }, // 5. 判斷是否以on:開頭的字符串 isEventDirective: function(dir) { return dir.indexOf('on:') === 0; }, // 7, 事件指令解析 // DOM標簽, vue對象, exp是key值, dir是事件名 compileEvent: function (node, vm, exp, dir) { // 截取:后面的事件名字(例click) let eventType = dir.split(':')[1]; // 獲取vue實例中的methods對應的對象, 然后拿到對應的方法體 let cb = vm.methods && vm.methods[exp]; if (eventType && cb) { // 給這個DOM注冊事件, eventType事件觸發, 調用此方法, 傳入vue實例對象進去(這就是你為什么在methods中可以直接使用this代表vue對象的原因) node.addEventListener(eventType, cb.bind(vm), false); } }, }; function Vue(options, exp) { this.data = options.data(); // 3. 綁定methods this.methods = options.methods; let self = this; Object.keys(this.data).forEach(function (key) { self.proxyKeys(key); }); observe(this.data); new Compile(options.el, this); options.mounted.call(this); } Vue.prototype = { proxyKeys: function (key) { let self = this; Object.defineProperty(this, key, { get: function () { return self.data[key]; }, set: function (newVal) { self.data[key] = newVal } }) } } </script> <div id="app"> <h1>{{userName}}</h1> <input type="text" v-model="userName"> <!--1. 使用v-on綁定click事件 --> <button v-on:click="btn">點我試試</button> </div> <script> new Vue({ el: "#app", data() { return { "userName": "hello VueJS" } }, mounted() { setTimeout(() => { this.userName = "漂亮"; }, 2000); }, // 2. 注冊methods methods: { btn() { this.userName = "點按鈕了"; } } }); </script> ~~~ [當前頁源代碼](https://github.com/lidongxuwork126com/ldx_vue/tree/master/%E4%BB%BFVue%E6%BA%90%E7%A0%81)