14.5 跨域 - document.domain

<!--
实现需要满足条件：域名 一级域名二级域名
www.baidu.com
video.baidu.com
a是通过 http://b.test.com:3000/a.html 访问
-->
Hello, A
<iframe src="http://b.test.com:3000/b.html"  onload="load()" id="frame"></iframe>
<script>
  document.domain = ‘test.com‘
  function load() {
      console.log(frame.contentWindow.a)
    }
</script>

<script>
    document.domain = ‘test.com‘
    var a = 100
</script>

let express = require(‘express‘)
let app  = express()
app.use(express.static(__dirname))
app.listen(3000)

let express = require(‘express‘)
let app  = express()
app.use(express.static(__dirname))
app.listen(4000)