chrome extension exchange data between popup and eventpage
// Inform the background page that
// this tab should have a page-action.
chrome.runtime.sendMessage({
from: 'content',
subject: 'showPageAction',
});
// Listen for messages from the popup.
chrome.runtime.onMessage.addListener((msg, sender, response) => {
// First, validate the message's structure.
if ((msg.from === 'popup') && (msg.subject === 'DOMInfo')) {
// Collect the necessary data.
// (For your specific requirements `document.querySelectorAll(...)`
// should be equivalent to jquery's `$(...)`.)
var domInfo = {
total: document.querySelectorAll('*').length,
inputs: document.querySelectorAll('input').length,
buttons: document.querySelectorAll('button').length,
};
// Directly respond to the sender (popup),
// through the specified callback.
response(domInfo);
}
});