Question

I’m trying to pass data that is saved in sessionStorage from background.html to popup.html

background.html:

chrome.extension.onRequest.addListener(function(request, sender, sendResponse) {
  data = sessionStorage.getItem(request.tabId);
  alert(data);
  sendResponse({ data: data });
});

and in popup.html:

chrome.tabs.getSelected(null, function(tab) {
  chrome.extension.sendRequest({ tabId: tab.id }, function(response) { 
    alert(response.data);
  });
});

The popup is opened by a pageAction button, when I click the button I get an alert box with “null” on the popup and then an alert box with the data that I stored in sessionStorage on the background!

Any ideas how to fix this?

Answer 1

Well, I’ve done something dumb.

I inspected the background page by opening chrome-extension://[extension-id]/background.html in a tab instead of clicking on “inspect active views: background.html” in the extensions management page. This caused the tab to catch the request and call sendResponse, but the popup expected the REAL background page to call sendResponse (and if I understand Google’s documentation regarding message passing, the fact that sendResponse was called twice is root of the problem, because the first call clears the request object)