simple answer:
if you have no response from another End it will also tell you Receiving end does not exist.
detailed answer:
if you have no answer from another end it will also tell you Receiving end does not exist. so if you have any callBack function which should use response in your .sendMessage part, you should either delete it or handle it if you probably have no response from another side.
so
if i wanted to re-write Simple one-time requests section of Message passing documents of google API i will write it with error handlers for callback functions in message-sending methods like this:
Sending a request from a content script looks like this:
chrome.runtime.sendMessage({greeting: "hello"}, function (response) {
if (!chrome.runtime.lastError) {
// if you have any response
} else {
// if you don't have any response it's ok but you should actually handle
// it and we are doing this when we are examining chrome.runtime.lastError
}
});
Sending a request from the extension to a content script looks very similar, except that you need to specify which tab to send it to. This example demonstrates sending a message to the content script in the selected tab.
chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
chrome.tabs.sendMessage(tabs[0].id, {greeting: "hello"}, function(response) {
if (!chrome.runtime.lastError) {
// if you have any response
} else {
// if you don't have any response it's ok but you should actually handle
// it and we are doing this when we are examining chrome.runtime.lastError
}
});
});
On the receiving end, you need to set up an runtime.onMessage event listener to handle the message. This looks the same from a content script or extension page.
chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse) {
console.log(sender.tab ?
"from a content script:" + sender.tab.url :
"from the extension");
if (request.greeting === "hello")
sendResponse({farewell: "goodbye"});
}
);
