diff --git a/src/js/shortcut.js b/src/js/shortcut.js
new file mode 100644
index 0000000..7959178
--- /dev/null
+++ b/src/js/shortcut.js
@@ -0,0 +1,35 @@
+var shortcutKey = {
+
+  init: function() {
+    if (document.body.hasAttribute('screen_capture_injected')) {
+      return;
+    }
+    document.body.setAttribute('screen_capture_injected', true);
+    document.body.addEventListener('keydown', shortcutKey.handleShortcut,
+      false);
+  },
+
+  isThisPlatform: function(operationSystem) {
+    return navigator.userAgent.toLowerCase().indexOf(operationSystem) > -1;
+  },
+
+  handleShortcut: function (event) {
+    var isMac = shortcutKey.isThisPlatform('mac');
+    var keyCode = event.keyCode;
+    // Send compose key like Ctrl + Alt + alphabetical-key to background.
+    if ((event.ctrlKey && event.altKey && !isMac ||
+          event.metaKey && event.altKey && isMac) &&
+        keyCode > 64 && keyCode < 91) {
+      shortcutKey.sendMessage({
+        msg: 'capture_hot_key',
+        keyCode: keyCode
+      });
+    }
+  },
+
+  sendMessage: function(message) {
+    chrome.extension.sendMessage(message);
+  }
+};
+
+shortcutKey.init();