diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..934a271
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,8 @@
+build:
+	./build.sh
+v2:
+	rm manifest.json \
+    ln -s manifest-v2.json manifest.json
+v3:
+	rm manifest.json \
+    ln -s manifest-v3.json manifest.json
diff --git a/README.md b/README.md
index 898712d..3dbd35d 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,10 @@ To be updated
         rm manifest.json
         ln -s manifest-v3.json manifest.json     
         ```
+        or simply 
+        ```shell
+        make v3
+        ```
     - Go to [chrome://extensions/](chrome://extensions/)
     - Click on `Load unpacked` button on the top left
     - Select the cloned repo
@@ -74,12 +78,16 @@ To be updated
         rm manifest.json
         ln -s manifest-v2.json manifest.json     
         ```
+        or simply
+        ```shell
+        make v2
+        ```
     - Go to [about:debugging#/runtime/this-firefox](about:debugging#/runtime/this-firefox)
     - Click on `Load Temporary Add-on`
     - Select the manifest.json file
     - Note that Chrome can also load manifest v2, but this will be deprecated in June 2023
 4. Package for distribution:
-    - Run `build.sh`
+    - Run `build.sh` (or `make build`)
     - The output zip files are in the `build` directory
 <!-- CONTRIBUTING -->
 ## Contributing
diff --git a/popup/popup.html b/popup/popup.html
index 99be40e..b53dedd 100644
--- a/popup/popup.html
+++ b/popup/popup.html
@@ -55,7 +55,7 @@
             <label for="check-interval" title="How often the spamminator search & remove spams">
                 Clear spam interval (in millisecond)
             </label>
-            <input id="check-interval" value="" type="number">
+            <input id="check-interval" value="" type="number" min="200" step="100">
         </div>
         <div>
             <label for="ban-domain" title="Require page refresh to take affect">
diff --git a/scripts/service-worker.js b/scripts/service-worker.js
index a1ac5c4..141c59e 100644
--- a/scripts/service-worker.js
+++ b/scripts/service-worker.js
@@ -32,7 +32,7 @@ async function migrateToVer1() {
     version: "1.0",
     banDomains: DEFAULT_BAN_DOMAINS,
     enable: true,
-    clearSpamInterval: 1000,
+    clearSpamInterval: 1500,
     cleanSpamAction: "replace-with-image",
     cleanSpamText: "",
     cleanSpamImage: "random",