What I want to do:

I am trying to build a chrome-extension. The extension will-

1. By clicking the icon once, it will keep running.
2. After that, on any page/tab, the user would be able to select some text and use a key combination (e.g. Shift+a) to send that text to an HTML page, say text.html.
3. If I click the icon again, the extension will stop working.

Note that text.html is a fixed page, all text will be accumulated on text.html.

My Attempt:

1. Run a JavaScript on background to collect text, then send it by using sendMessage, something like :

content.js

function getSelectionText() {
    var text = "";
    if (window.getSelection) {
        text = window.getSelection().toString();
    } else if (document.selection && document.selection.type != "Control") {
        text = document.selection.createRange().text;
    }
    return text;
}
function doc_keyUp(e) {
    // this would test for whichever key is 40 (down arrow) and the ctrl key at the same time
    if (e.key === 'a') {
       tx_s=getSelectionText();
       //console.log(tx_s);
       chrome.runtime.sendMessage({greeting:tx_s},function(response) {console.log(response.farewell);}); 

                 
                      }// if (e.key === 'q')
                     } // doc_keyUp(e)
// register the handler 
document.addEventListener('keyup', doc_keyUp, false);

it receives text by the below code:

background.js

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:request.greeting});   
                               console.log(request.greeting);                             
                               //window.greeting[0] = request.greeting;
                              })
                              
chrome.action.onClicked.addListener(function (tab) {
  chrome.tabs.create({url: 'popup.html'})
})

2. Then get the textto the HTML file, I got the idea from "How To Make Chrome Extensions", Kyle Robinson Young (click here), but the code is not working due to manifes version problem, also the code gets error window.bears={}; (does not allow window option).

How can I transfer the text from various page to a accumlate and view on a html? Thanks.