diff --git a/src/wxsy.net/fetch.py b/src/wxsy.net/fetch.py
index 5d7e142..eb057b6 100644
--- a/src/wxsy.net/fetch.py
+++ b/src/wxsy.net/fetch.py
@@ -7,6 +7,7 @@ Download raw html content as `.html` files.
     USAGE: python3 fetch.py [CATALOG] [OUTPUT_DIR]
 """
 
+import os
 import sys
 import json
 import time
@@ -20,21 +21,21 @@ userAgent = (  # default user agent
 )
 
 
-def httpRequest(url: str, fileName: str) -> bool:  # save html content
+def httpRequest(fileUrl: str, fileName: str) -> bool:  # save html content
     try:
-        logger.debug('Http request `%s` -> %s' % (url, fileName))
-        request = requests.get(url, timeout = 30,  # timeout -> 30s
+        logger.debug('Http request `%s` -> `%s`' % (fileUrl, fileName))
+        request = requests.get(fileUrl, timeout = 30,  # timeout -> 30s
             headers = {
                 'user-agent': userAgent,  # with fake user-agent
             }
         )
         if request.status_code not in range(200, 300):  # http status code 2xx
-            logger.warning('Http request failed -> %s' % url)
+            logger.warning('Http request failed -> `%s`' % fileUrl)
             return False
-        logger.debug('Http request success -> %s' % url)
+        logger.debug('Http request success -> `%s`' % fileUrl)
         with open(fileName, 'w') as fileObj:  # save html content
             fileObj.write(request.text)
-        logger.debug('File save success -> %s' % fileName)
+        logger.debug('File save success -> `%s`' % fileName)
     except:
         return False
     return True
@@ -44,7 +45,7 @@ catalog = json.loads(open(sys.argv[1]).read())  # load catalog
 
 for _, chapterId in catalog.items():  # traverse all chapters
     pageUrl = 'https://www.wxsy.net/novel/57104/read_%s.html' % chapterId
-    pageFile = '%s/%s.html' % (sys.argv[2], chapterId)
+    pageFile = os.path.join(sys.argv[2], '%s.html' % chapterId)
     if httpRequest(pageUrl, pageFile):  # save html content
         logger.info('Page request success -> %s' % pageUrl)
     else: