akirattii

/*****************************************************************
 * onMessage from the extension or tab (a content script)
 *****************************************************************/
chrome.runtime.onMessage.addListener(
  function(request, sender, sendResponse) {
    if (request.cmd == "any command") {
      sendResponse({ result: "any response from background" });
    } else {
      sendResponse({ result: "error", message: `Invalid 'cmd'` });
    }