diff --git a/.env b/.env
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--- /dev/null
+++ b/.env
@@ -0,0 +1,3 @@
+# Chaoxing cookie string
+CHAOXING_COOKIE=fid=22281; _uid=370760372; UID=370760372; xxtenc=15584f359efe687c74210d6c8cf8c868; _d=1760090294927; vc3=bHu2bElQMQReXPqcrAF4lIAmOTgbQixqKbazxIRmLhBjc3MWE4wQKcxU6x%2Fwk%2BFiHHIdcMaDXNZToWGkbPBqTQhWnSh%2B%2BI2w%2BUHw4VaOxA1KVmTNdwXZa%2BQ%2B%2Bbarpltdw9ejb6ADyrGJg62Z5WY5At563Ln%2BV0XLSdiZziphB2g%3D473692a83f01ba73d93a227e641ded15; uf=da0883eb5260151ee7907b77259a9bebb037741b6ebd8a0e7b1ca06f23f166cf20e018dfde10b39f3897f0bbb44fe3fc190a36865f1aaba0c49d67c0c30ca5043ad701c8b4cc548c0234d89f51c3dccf7b33a24f3acfc547713028f1ec42bf71b1188854805578ccf8e9874e39b83496200dbd5a47ba3976cb5694cefd263e7fb246307f6edc53a5991f5511a8c2c4044df7ff280fcb29d10d8a4c92b12beb4b9d97dfe5b26c691c53cff74943fa500768a63fc9f8959a8ee7fafd565af53bf2; cx_p_token=6ce221216032ecce040f924eec576927; p_auth_token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1aWQiOiIzNzA3NjAzNzIiLCJsb2dpblRpbWUiOjE3NjAwOTAyOTQ5MjgsImV4cCI6MTc2MDY5NTA5NH0.HPJEsTAQmVcRb8KTH83JGttOh4GN9uWqujODvsHBq1g; DSSTASH_LOG=C_38-UN_646-US_370760372-T_1760090294929; tl=1; k8s=1760153245.393.18079.162885; route=3cfd8ee391150acbf63626fecc6e7627; writenote=yes; jrose=C29882EB86BF280B84636EAEE5A1B40F.mooc-523979977-14p9h; videojs_id=59724
+COURSE_URL=https://mooc1.chaoxing.com/mycourse/studentstudy?chapterId=1050488737&courseId=256005147&clazzid=129437493&cpi=441843723&enc=aa5f995e880be44ade430110fb11c896&mooc2=1&openc=6e7668af7a831729d3f3b56ee34a66ad
\ No newline at end of file
diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
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+# Chaoxing 课程字幕批量下载工具
+
+本项目包含自动化脚本，可批量提取超星课程视频字幕（SRT），支持 Cookie 配置和多课程处理。
+
+## 使用方法
+
+### 1. 环境准备
+- 安装 Python 3.x
+- 安装依赖包：
+  ```bash
+  pip install requests beautifulsoup4 python-dotenv
+  ```
+
+### 2. 配置 Cookie
+- 在项目根目录下创建 `.env` 文件（已自动生成），内容如下：
+  ```env
+  CHAOXING_COOKIE=你的超星登录Cookie
+  ```
+- 如 Cookie 过期或更换账号，直接修改 `.env` 文件即可。
+
+### 3. 下载课程 HTML
+- 用浏览器保存你要下载字幕的课程页面（建议保存课程目录页或视频列表页），如 `course.html`。
+- 将 HTML 文件放到脚本所在目录。
+
+### 4. 提取字幕 JSON 链接
+- 运行 `subtitle_downloader.py`，自动解析 HTML，提取所有字幕 JSON 链接，保存为 `subtitles/课程名.txt`。
+  ```bash
+  python subtitle_downloader.py
+  ```
+- 如需处理其他课程，只需更换 HTML 文件并重新运行脚本。
+
+### 5. 下载 SRT 字幕文件
+- 运行 `srt_fetcher.py`，自动读取 `subtitles/` 下所有 `.txt`，下载对应 SRT 文件到 `srt/` 文件夹。
+  ```bash
+  python srt_fetcher.py
+  ```
+
+## 文件说明
+- `downloader.py`：通用文件下载脚本（如需下载其他资源可用）
+- `subtitle_downloader.py`：解析课程 HTML，提取字幕 JSON 链接
+- `srt_fetcher.py`：批量下载 SRT 字幕文件
+- `.env`：存储 Cookie
+- `subtitles/`：保存每个课程的字幕 JSON 链接
+- `srt/`：保存下载的 SRT 字幕文件
+
+## 常见问题
+- Cookie 失效：请重新获取并更新 `.env` 文件
+- 页面结构变化：如遇解析失败，请反馈或自行调整 `subtitle_downloader.py` 的解析逻辑
+- SRT 下载失败：检查 Cookie 是否有效，或字幕 JSON 链接是否正确
+
+## 免责声明
+本脚本仅供学习交流使用，请勿用于任何商业或非法用途。
diff --git a/subtitle_downloader.py b/subtitle_downloader.py
new file mode 100644
index 0000000..6e3c8e0
--- /dev/null
+++ b/subtitle_downloader.py
@@ -0,0 +1,282 @@
+from __future__ import annotations
+
+import json
+import os
+import re
+import time
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Dict, Iterable, List, Optional
+
+import requests
+from bs4 import BeautifulSoup
+from dotenv import load_dotenv
+
+# Constants for the Chaoxing endpoints
+CARDS_URL = "https://mooc1.chaoxing.com/mooc-ans/knowledge/cards"
+# Primary endpoints visible in cards payload / player scripts
+RICH_SUBTITLE_URL = "https://mooc1.chaoxing.com/mooc-ans/richvideo/subtitle"
+RICH_ALLSUBTITLE_URL = "https://mooc1.chaoxing.com/mooc-ans/richvideo/allsubtitle"
+# Fallback (may return 500 depending on auth):
+EDITOR_SUBTITLE_URL = "https://mooc1.chaoxing.com/ananas/video-editor/sub"
+
+# Regex helpers
+_ONCLICK_RE = re.compile(r"getTeacherAjax\('(?P<course>\d+)',\s*'(?P<class>\d+)',\s*'(?P<knowledge>\d+)'\)")
+_JSON_RE = re.compile(r"mArg\s*=\s*(\{.*?\});", re.DOTALL)
+_INVALID_FILENAME_RE = re.compile(r"[\\/:*?\"<>|]")
+
+
+@dataclass(frozen=True)
+class KnowledgeEntry:
+    knowledge_id: str
+    title: str
+
+
+def load_cookie_from_env(env_var: str = "CHAOXING_COOKIE") -> Dict[str, str]:
+    """Parse a raw cookie string from environment variables into a dict."""
+    # Load .env values into environment first
+    try:
+        load_dotenv()
+    except Exception:
+        pass
+    raw_cookie = os.getenv(env_var, "").strip()
+    cookies: Dict[str, str] = {}
+    if not raw_cookie:
+        return cookies
+    for fragment in raw_cookie.split(";"):
+        if not fragment.strip():
+            continue
+        if "=" not in fragment:
+            continue
+        name, value = fragment.split("=", 1)
+        cookies[name.strip()] = value.strip()
+    return cookies
+
+
+def sanitize_filename(name: str) -> str:
+    """Turn a lesson title into a safe filename for Windows."""
+    cleaned = _INVALID_FILENAME_RE.sub("_", name)
+    return cleaned.strip() or "untitled"
+
+
+def parse_knowledge_entries(html_path: Path) -> List[KnowledgeEntry]:
+    """Scan the saved HTML page and extract all knowledge entries."""
+    soup = BeautifulSoup(html_path.read_text(encoding="utf-8"), "html.parser")
+    entries: Dict[str, KnowledgeEntry] = {}
+    for span in soup.select("span.posCatalog_name"):
+        onclick = span.get("onclick", "")
+        match = _ONCLICK_RE.search(onclick)
+        if not match:
+            continue
+        knowledge_id = match["knowledge"]
+        title_attr = span.get("title") or span.get_text(strip=True)
+        title = " ".join(title_attr.split())
+        if knowledge_id not in entries:
+            entries[knowledge_id] = KnowledgeEntry(knowledge_id=knowledge_id, title=title)
+    return list(entries.values())
+
+
+def extract_marg_json(cards_html: str) -> Optional[dict]:
+    """Pull the mArg JSON payload from a cards response."""
+    match = _JSON_RE.search(cards_html)
+    if not match:
+        return None
+    json_block = match.group(1)
+    # Fix JavaScript style booleans/nulls if necessary
+    json_block = json_block.replace("\n", " ")
+    try:
+        return json.loads(json_block)
+    except json.JSONDecodeError:
+        # Try to sanitize single quotes inside keys by using eval-safe replacement
+        sanitized = json_block
+        sanitized = sanitized.replace("'", '\"')
+        try:
+            return json.loads(sanitized)
+        except json.JSONDecodeError:
+            return None
+
+def load_local_cards_marg(cards_dir: Path, knowledge_id: str) -> Optional[dict]:
+    """Try to parse saved cards.html to get mArg when network call fails."""
+    # Saved file path observed: 学生学习页面_files/cards.html
+    candidate = cards_dir / "cards.html"
+    if not candidate.exists():
+        return None
+    try:
+        text = candidate.read_text(encoding="utf-8", errors="ignore")
+        marg = extract_marg_json(text)
+        # Optionally ensure the knowledgeid matches
+        if marg and str(marg.get("defaults", {}).get("knowledgeid")) == str(knowledge_id):
+            return marg
+        return marg
+    except Exception:
+        return None
+
+
+def iter_video_attachments(marg: dict) -> Iterable[dict]:
+    """Yield the attachment dicts that correspond to videos."""
+    attachments = marg.get("attachments") or []
+    for attachment in attachments:
+        if attachment.get("type") == "video":
+            yield attachment
+
+def is_html_error(text: str) -> bool:
+    t = text.strip().lower()
+    return t.startswith("<!doctype html>") and ("500" in t or "用户登录" in t)
+
+
+def fetch_cards(session: requests.Session, knowledge_id: str, base_params: Dict[str, str]) -> Optional[dict]:
+    params = dict(base_params)
+    params["knowledgeid"] = knowledge_id
+    response = session.get(CARDS_URL, params=params, timeout=10)
+    if response.status_code != 200:
+        print(f"[WARN] Failed to load cards for knowledge {knowledge_id}: HTTP {response.status_code}")
+        return None
+    marg = extract_marg_json(response.text)
+    if marg is None:
+        # Fallback: try local saved cards
+        cards_dir = Path("学生学习页面_files")
+        marg = load_local_cards_marg(cards_dir, knowledge_id)
+        if marg is None:
+            print(f"[WARN] Could not locate mArg JSON for knowledge {knowledge_id}")
+    return marg
+
+
+def download_subtitle(session: requests.Session, marg: dict, object_id: str, mid: Optional[str], course_id: str, output_path: Path) -> bool:
+    # Try richvideo/allsubtitle first (more complete), then richvideo/subtitle, then editor fallback
+    tried = []
+    def try_get(url: str, params: dict) -> Optional[str]:
+        tried.append((url, params))
+        r = session.get(url, params=params, timeout=10)
+        if r.status_code != 200:
+            return None
+        if not r.text.strip() or is_html_error(r.text):
+            return None
+        return r.text
+
+    # Prefer objectId and mid
+    subtitle_url_base = marg.get("defaults", {}).get("subtitleUrl") or RICH_SUBTITLE_URL
+    # 1) allsubtitle
+    params_all = {"mid": mid or marg.get("attachments", [{}])[0].get("mid"), "objectid": object_id, "courseId": course_id}
+    text = try_get(RICH_ALLSUBTITLE_URL, params_all)
+    if not text:
+        # 2) subtitle
+        params_sub = {"mid": params_all["mid"], "objectid": object_id, "courseId": course_id}
+        text = try_get(RICH_SUBTITLE_URL, params_sub)
+    if not text:
+        # 3) fallback editor endpoint
+        text = try_get(EDITOR_SUBTITLE_URL, {"objectid": object_id})
+    if text:
+        output_path.write_text(text, encoding="utf-8")
+        print(f"[INFO] Saved subtitle to {output_path}")
+        return True
+    print(f"[WARN] Subtitle download failed for object {object_id}. Tried: {tried}")
+    return False
+
+
+def main() -> None:
+    load_dotenv()
+    html_path = Path("学生学习页面.html")
+    course_url = os.getenv("COURSE_URL", "").strip()
+    if not html_path.exists():
+        if course_url:
+            print(f"[INFO] 本地HTML不存在，自动下载课程页面: {course_url}")
+            cookies = load_cookie_from_env()
+            session = requests.Session()
+            session.headers.update({
+                "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0 Safari/537.36",
+                "Referer": course_url,
+            })
+            if cookies:
+                session.cookies.update(cookies)
+            resp = session.get(course_url, timeout=15)
+            if resp.status_code == 200 and resp.text:
+                html_path.write_text(resp.text, encoding="utf-8")
+                print(f"[INFO] 已保存课程页面到 {html_path}")
+            else:
+                raise SystemExit(f"下载课程页面失败: HTTP {resp.status_code}")
+        else:
+            raise SystemExit("学生学习页面.html not found, 且未配置 COURSE_URL")
+
+    entries = parse_knowledge_entries(html_path)
+    if not entries:
+        raise SystemExit("No knowledge entries found in saved HTML")
+    print(f"[INFO] Found {len(entries)} lessons")
+
+    session = requests.Session()
+    session.headers.update({
+        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0 Safari/537.36",
+        "Referer": "https://mooc1.chaoxing.com/",
+    })
+    cookies = load_cookie_from_env()
+    if cookies:
+        session.cookies.update(cookies)
+        print(f"[INFO] Loaded {len(cookies)} cookies from environment")
+    else:
+        print("[WARN] No cookies provided. Requests may fail if authentication is required.")
+
+    base_params = {
+        "clazzid": "129437493",
+        "courseid": "256005147",
+        "num": "0",
+        "ut": "s",
+        "cpi": "441843723",
+        "mooc2": "1",
+        "isMicroCourse": "",
+        "editorPreview": "",
+    }
+
+
+    # 步骤1：下载字幕 JSON
+    output_dir = Path("subtitles")
+    output_dir.mkdir(exist_ok=True)
+    for entry in entries:
+        print(f"[INFO] Processing {entry.title} (knowledge {entry.knowledge_id})")
+        marg = fetch_cards(session, entry.knowledge_id, base_params)
+        if not marg:
+            continue
+        video_found = False
+        for attachment in iter_video_attachments(marg):
+            video_found = True
+            object_id = attachment.get("objectId") or attachment.get("property", {}).get("objectid")
+            mid = attachment.get("mid") or attachment.get("property", {}).get("mid")
+            if not object_id:
+                print(f"[WARN] No objectId for lesson {entry.title}")
+                continue
+            filename = sanitize_filename(entry.title) + ".txt"
+            output_path = output_dir / filename
+            if download_subtitle(session, marg, object_id, mid, base_params["courseid"], output_path):
+                time.sleep(0.5)
+        if not video_found:
+            print(f"[WARN] No video attachments found for {entry.title}")
+
+    # 步骤2：批量下载 SRT 文件
+    srt_dir = Path("srt")
+    srt_dir.mkdir(exist_ok=True)
+    def fetch_srt(url: str, session: requests.Session) -> str | None:
+        r = session.get(url, timeout=10)
+        if r.status_code == 200 and r.text.strip():
+            return r.text
+        return None
+
+    for txt_file in output_dir.glob("*.txt"):
+        try:
+            content = txt_file.read_text(encoding="utf-8").strip()
+            data = json.loads(content)
+            # data is list of tracks
+            for track in data:
+                url = track.get("url")
+                if not url:
+                    continue
+                srt_text = fetch_srt(url, session)
+                if not srt_text:
+                    print(f"[WARN] Failed to fetch SRT from {url}")
+                    continue
+                name = txt_file.stem + ".srt"
+                out_path = srt_dir / name
+                out_path.write_text(srt_text, encoding="utf-8")
+                print(f"[INFO] Saved {out_path}")
+        except Exception as e:
+            print(f"[WARN] {txt_file.name}: {e}")
+
+if __name__ == "__main__":
+    main()