nodejs 提供了一个 node-uuid 模块用于生成 uuid:
首先执行：npm install node-uuid
var uuid = require('node-uuid');
console.log(uuid.v1())
console.log(uuid.v4())
v1 是基于时间戳生成uuid
v4是随机生成uuid
结果：
57af5b10-3a76-11e5-922a-75f42afeee38
f3917fb9-9bde-4ec1-a7cf-966251b3d22a
