VirtualDOM是一个JavaScriptDOM模型，支持元素创建，区别计算和分支操作，提供高效的渲染。代码示例var h = require('virtual-dom/h');var diff = require('virtual-dom/diff');var patch = require('virtual-dom/patch');var createElement = require('virtual-dom/create-element');// 1: Create a function that declares what the DOM shoul