哈哈哈，今天才知道谷歌浏览器同时只能对同一个 URL 提出一个请求。

// 我用的测试代码

package main

import (
    "log"
    "net/http"
    "time"
)

type Server struct {
    lock bool
}

func (s *Server) listen(port string) {
    mux := http.NewServeMux()
    mux.HandleFunc("/a", s.testHandler)
    mux.HandleFunc("/b", s.testHandler)
    mux.HandleFunc("/c", s.testHandler)
    mux.HandleFunc("/d", s.testHandler)
    mux.HandleFunc("/e", s.testHandler)
    mux.HandleFunc("/f", s.testHandler)
    mux.HandleFunc("/g", s.testHandler)
    mux.HandleFunc("/h", s.testHandler)
    mux.HandleFunc("/i", s.testHandler)
    mux.HandleFunc("/j", s.testHandler)
    http.ListenAndServe(":"+port, mux)
}

func (s *Server) testHandler(w http.ResponseWriter, r *http.Request) {
    log.Println("here")
    if s.lock == true {
        w.Write([]byte("locked"))
        log.Println("locked")
        return
    }
    s.lock = true

    time.Sleep(60 * time.Second)
    s.lock = false
    log.Println("unlocked")
    w.Write([]byte("unlocked"))
}

func main() {
    server := Server{
        lock: false,
    }

    server.listen("8888")
}

Console 控制台测试同时打开

// console 控制台同时打开下面这组会阻塞，但是过几秒很奇怪的是后面九条是同时完成
window.open("http://127.0.0.1:8888/a");
window.open("http://127.0.0.1:8888/a");
window.open("http://127.0.0.1:8888/a");
window.open("http://127.0.0.1:8888/a");
window.open("http://127.0.0.1:8888/a");
window.open("http://127.0.0.1:8888/a");

// console 控制台不会阻塞
window.open("http://127.0.0.1:8888/a");
window.open("http://127.0.0.1:8888/b");
window.open("http://127.0.0.1:8888/c");
window.open("http://127.0.0.1:8888/d");
window.open("http://127.0.0.1:8888/e");
window.open("http://127.0.0.1:8888/f");