package main

import (
    "io"
    "net/http"
)

func main() {
    http.HandleFunc("/", foo)
    http.Handle("/favicon.ico", http.NotFoundHandler())
    http.ListenAndServe(":8080", nil)
}

func foo(w http.ResponseWriter, req *http.Request) {
    v := req.FormValue("q")
    w.Header().Set("Content-Type", "text/html; charset=utf-8")
    io.WriteString(w, `
        <form method="post">
            <input type="text" name="q">
            <input type="submit">
        </form>
        <br>`+v)
}