Chrome扩展程序中脚本之间的通信

Question

I know there are many variations of this question already in existence here, but none of them seem to work for me.

Details:

I'm writing an extension that pulls some email data from emails you send in gmail. In order to achieve this I am using this version of Gmailr https://github.com/joscha/gmailr .

In effect, I have three content scripts: Gmailr.js and main.js (which are pretty much identical to those in the link above) allow me to pull out the information I'm looking for. Then content.js I use to send a message to the background page of the extension.

The problem is that from gmailr.js and main.js I cannot use any of the Chrome APIs, and I'm not really sure why, so I can't send messages from these back to the background page.

That is why I made content.js which can communicate with the background page. However, it does not seem to be able to see anything the other content scripts do. For example, main.js inserts a div at the top of the page. When I try to attach an event listener to a button in this div from content.js, I am told that no such element exists.

How can I get the data pulled out by main.js to be seen by content.js? (I also tried to put the data in local storage, then trigger a custom event listener to tell content.js to read local storage, but no luck because they don't seem to be able to hear each other's event being triggered).

Any insight or alternatives are much appreciated.

(I can post code if necessary, but it's fragmented and long)

My manifest file:

{
  "manifest_version": 2,
  "name": "Email extractor",
  "description": "Extracts data from emails",
  "version": "1.0",
  "background": {
     "script": "background.js"
  },
  "content_scripts": [
    {
      "matches": [
        "*://mail.google.com/*",
        "*://*/*"
      ],
      "js": [
        "lib/yepnope.js/yepnope.1.5.4-min.js",
        "lib/bootstrap.js",
        "main.js",
        "gmailr.js",
        "content.js"

      ],
      "css": [
        "main.css"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "tabs",
    "storage",
    "background",
    "*://mail.google.com/*",
    "*://*/*"
  ],

  "browser_action": {
    "default_icon": "img/icon.png",
    "default_popup": "popup.html"
  },

  "web_accessible_resources" : [
    "writeForm.js",
    "disp.js",
    "/calendar/jsDatePick.min.1.3.js",
    "/calendar/jsDatePick_ltr.min.css",
    "lib/gmailr.js",
    "lib/jquery-bbq/jquery.ba-bbq.min.js",
    "content.js",
    "main.js",
    "background.js"
  ]
} 

This is main.js:

Gmailr.init(function(G) {
    sender = G.emailAddress();
    G.insertTop($("<div id='gmailr'><span></span> <span id='status'></span>)");
    el = document.getElementById("testid");
    el.addEventListener('click', mg, false);
    var status = function(msg) {
       G.$('#gmailr #status').html(msg); };    
       G.observe(Gmailr.EVENT_COMPOSE, function(details) {        
         ....
         status(" user: " + user);
         console.log('user:', user);
         //now try to send a message to the background page
         //this always returns the error that method sendMessage does not exist for     undefined
        chrome.runtime.sendMessage({greeting: "test from gmailr"}, function(response) {
        console.log("did it send?");
        });
    });


});

gmailr.js is quite long and is also not my own code but it can be seen here: http://pastebin.com/pK4EG9vh

Answer 1

Hi perhaps 3 likely reason to your problem :

1. The way you send messages to bgp from main.js and gmailr.js are perhaps wrong because you must arrive to communicate from any content script to your bgp. (in your manifest content script key the gmailr.js is missing). Show us your code it would help.

2. You seems to have a problem with the moment you search from content.js to access to the element created in main.js. Do you try to access your element with the jQuery $("").on() method ? A simple test must be to declare a function in one cs and to use it in another. If it's not working it's a manifest problem. The order you declare .js file in manifest content script key is important also.

3. try to in the manifest content script array "run_at":"document_end"

Hope it help !