[TOC] ## 概述 语法 ``` interface Headers { append(name: string, value: string): void; delete(name: string): void; get(name: string): string | null; has(name: string): boolean; set(name: string, value: string): void; forEach(callbackfn: (value: string, key: string, parent: Headers) => void, thisArg?: any): void; } declare var Headers: { prototype: Headers; new(init?: HeadersInit): Headers; }; ```