Use W3C Fetch API instead of hacky JS

main.go

@@ -79,7 +79,15 @@ function disp(rendus) {
       <tbody id="students">
       </tbody>
     </table>
-    <script src="rendus.json?func=disp"></script>
+    <script type="text/javascript">
+    fetch('rendus.json') // You can also fetch login_x.json
+      .then(function(response) {
+         return response.json();
+      })
+      .then(function(submissions) {
+        disp(submissions);
+      });
+    </script>
   </body>
 </html>
 `))
@@ -99,35 +107,13 @@ func genStudents() map[string]map[string]*Submission {
 func ServeJSON(w http.ResponseWriter, r *http.Request) {
 	log.Printf("Handling %s request from %s: %s [%s]\n", r.Method, r.RemoteAddr, r.URL.Path, r.UserAgent())
 
-	q := r.URL.Query()
-	varname := q.Get("var")
-	funcname := q.Get("func")
-
-	if funcname == "" && varname == "" {
-		w.Header().Set("Content-Type", "application/json")
-	} else {
-		w.Header().Set("Content-Type", "application/javascript")
-	}
+	w.Header().Set("Content-Type", "application/json")
 
 	if j, err := json.Marshal(genStudents()); err != nil {
 		http.Error(w, fmt.Sprintf("{errmsg:%q}", err), http.StatusInternalServerError)
 	} else {
 		w.WriteHeader(http.StatusOK)
-		if varname != "" {
-			w.Write([]byte("var "))
-			w.Write([]byte(varname))
-			w.Write([]byte(" = "))
-		}
-		if funcname != "" {
-			w.Write([]byte(funcname))
-			w.Write([]byte("("))
-		}
 		w.Write(j)
-		if funcname != "" {
-			w.Write([]byte(")"))
-		} else if varname != "" {
-			w.Write([]byte(";"))
-		}
 	}
 }
 
@@ -166,22 +152,11 @@ func ServeJSONStudent(w http.ResponseWriter, r *http.Request) {
 
 	login := strings.TrimSuffix(strings.TrimPrefix(r.URL.Path, "/"), ".json")
 
-	q := r.URL.Query()
-	varname := q.Get("var")
-
 	if j, err := json.Marshal(genStudent(login)); err != nil {
 		http.Error(w, fmt.Sprintf("{errmsg:%q}", err), http.StatusInternalServerError)
 	} else {
 		w.WriteHeader(http.StatusOK)
-		if varname != "" {
-			w.Write([]byte("var "))
-			w.Write([]byte(varname))
-			w.Write([]byte(" = "))
-		}
 		w.Write(j)
-		if varname != "" {
-			w.Write([]byte(";"))
-		}
 	}
 }