Fix network error: Change API URL from localhost to relative path

static/tester.html

@@ -103,8 +103,7 @@
 
         <div class="form-group">
             <label for="apiUrl">API Endpoint URL</label>
-            <input type="text" id="apiUrl" value="http://127.0.0.1:8000/detect"
-                placeholder="http://127.0.0.1:8000/detect">
+            <input type="text" id="apiUrl" value="/detect" placeholder="/detect">
         </div>
 
         <div class="form-group">