为什么FormData为空？

Question

我已关注this guide on MDN。

var formData = new FormData();    
formData.append("username", "Groucho");
formData.append("accountnum", 123456);
console.log(formData);

为什么formData为空？

Answer 1

他们可以访问FormData

var formData = new FormData();

formData.append("username", "Groucho");
formData.append("accountnum", 123456);

console.log(formData.get("username"));
console.log(formData.get("accountnum"));