diff --git a/quickjs/src/main.rs b/quickjs/src/main.rs
index 2ef4694..36e4537 100644
--- a/quickjs/src/main.rs
+++ b/quickjs/src/main.rs
@@ -1,13 +1,34 @@
 use quick_js::Context;
+use quick_js::JsValue;
+use quick_js::console::Level;
+use quick_js::console::ConsoleBackend;
+
+struct ConsoleBackendImpl;
+impl ConsoleBackend for ConsoleBackendImpl {
+    fn log(&self, level: Level, values: Vec<JsValue>) {
+        // match level {
+        //     Level::Trace => {},
+        //     Level::Debug => {},
+        //     Level::Log   => {},
+        //     Level::Info  => {},
+        //     Level::Warn  => {},
+        //     Level::Error => {},
+        // }
+        println!("[{:>5}] - {:?}", format!("{:?}", level).to_uppercase(), values);
+    }
+}
 
 fn main() {
-    let context = Context::new().unwrap();
+    let context = Context::builder().memory_limit(16 * 1024 * 1024)
+                                    .console(ConsoleBackendImpl{})
+                                    .build()
+                                    .unwrap();
 
     let value = context.eval("1 + 2").unwrap();
     println!("js: 1 + 2 = {:?}", value);
 
     context.add_callback("myCallback", |a: i32, b: i32| a + b * b).unwrap();
-    let script = r#"   var x = myCallback(10, 20);  x;    "#;
+    let script = r#" console.debug('this is log');  var x = myCallback(10, 20);  x;    "#;
 
     let value = context.eval(script).unwrap();
     println!("js: callback = {:?}", value);