http请求如何兼容https或http请求指向http，https请求指向https

方法一：

请求地址前获取 location.protocol 拿到当前的 http | https 替换到请求地址的前缀

如：http://www.com, location.protocol 获取到 http: | https，将地址分割动态拼 location.protocol 

方法二：

获取location.protocol 动态创建meat标签

const protocol = location.protocol

    if(protocol && protocol ==='https:') {

      const meta = document.createElement('meta')

      meta.httpEquiv = 'Content-Security-Policy'

      meta.content = "upgrade-insecure-requests"

      document.getElementsByTagName('head')[0].appendChild(meta);

    }