diff --git a/.gitignore b/.gitignore
index 1d74e21..7aa1a6e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,4 @@
 .vscode/
+
+_metadata/
+.DS_Store
\ No newline at end of file
diff --git a/manifest.json b/manifest.json
index 8d1d3fe..494a300 100644
--- a/manifest.json
+++ b/manifest.json
@@ -110,13 +110,22 @@
     "tabs",
     "activeTab",
     "cookies",
-    "downloads"
+    "downloads",
+    "webRequest",
+    "declarativeNetRequest"
   ],
   "host_permissions": [
     "https://hkuportal.hku.hk/*",
     "https://moodle.hku.hk/*",
     "https://booking.lib.hku.hk/*"
   ],
+  "declarative_net_request": {
+    "rule_resources": [{
+      "id": "ruleset_1",
+      "enabled": true,
+      "path": "rules/moodle_pdf_download_rules.json"
+    }]
+  },
   "icons": {
     "16": "images/icon16.png",
     "32": "images/icon32.png",
diff --git a/rules/moodle_pdf_download_rules.json b/rules/moodle_pdf_download_rules.json
new file mode 100644
index 0000000..3f11828
--- /dev/null
+++ b/rules/moodle_pdf_download_rules.json
@@ -0,0 +1,18 @@
+[{
+  "id": 1,
+  "priority": 1,
+  "action": {
+    "type": "redirect",
+    "redirect": {
+      "transform": {
+        "queryTransform": {
+          "removeParams": ["forcedownload"]
+        }
+      }
+    }
+  },
+  "condition": {
+    "urlFilter": "https://moodle.hku.hk/pluginfile.php",
+    "resourceTypes": ["main_frame", "sub_frame", "object", "xmlhttprequest", "stylesheet", "script"]
+  }
+}]
\ No newline at end of file