Untitled

package main

import (
    "html/template"
    "net/http"
)

var tpl *template.Template

func init() { tpl = template.Must(template.ParseGlob("templates/*.gohtml")) }

type person struct {
    Fname string
    Lname string
    Sub   bool
}

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

func index(res http.ResponseWriter, req *http.Request) {
    if req.Method == http.MethodPost {
        f := req.FormValue("first")
        l := req.FormValue("last")
        s := req.FormValue("sub") == "on"
        user := person{f, l, s}
        tpl.ExecuteTemplate(res, "one.gohtml", user)
    } else {
        tpl.ExecuteTemplate(res, "one.gohtml", nil)
    }
}
==============================
<html>
<body>
    <form method="Post">
        first name: <input type="text" name="first"><br>
        last name: <input type="text" name="last"><br>
        sub : <input type="checkbox" name="sub"><br>
        <input type="submit"><br>
    </form>
    {{if and .Fname .Lname}}
        {{if and .Fname .Lname .Sub}}
            <h4>{{.Fname}} {{.Lname}} - {{.Sub}}</h4>
            {{template "two"}}
        {{else}}
            <h4>{{.Fname}} {{.Lname}}</h4>
        {{end}}
    {{else}}
        <h4>Something is missing</h4>
    {{end}}
</body>
</html>
{{define "two"}}
    You filled all boxes, thank you.
{{end}}