manifest_version代表此扩展程序使用的 manifest.json 版本，目前主流版本为2，最新版本为3

自2023年起，Chrome应用商店将不再接受Manifest V2扩展，构建新扩展需要升级到Manifest V3。以下为Manifest V2支持时间线：

1. page_action和browser_action在MV3中统一到action下

// Manifest v2
"browser_action": {...}
"page_action": {
    "default_icon": "images/icon.png",
    "default_title": "Banner开发调试插件",
    "default_popup": "index.html"
},

// Manifest v3
"action": {...}

2. 在MV3中，background persistent被弃用，background scripts被替换为background service_worker

// Manifest v2
"background": {
    "scripts": ["static/js/background.js"],
    "persistent": true
},

// Manifest v3
"background": {
    "service_worker": "static/js/background.js"
},

3. web_accessible_resources类型由字符串数组变更为对象

// Manifest v2
"web_accessible_resources": ["/static/js/*.js"]

// Manifest v3
"web_accessible_resources": [
    {
      "resources": [
        "/static/js/*.js"
      ],
      "matches": [
        "<all_urls>"
      ],
      "extension_ids": []
    }
],

4. content_security_policy类型由字符串变更为对象，并且script-src和worker-src指令可能只有这些值 ：‘self’, ‘none’, ‘wasm-unsafe-eval’

// Manifest v2
"content_security_policy": "default-src 'self'"

// Manifest v3
"content_security_policy": {
    "extension_pages": "script-src 'self' 'wasm-unsafe-eval'; object-src 'self'"
}

在MV2中，chrome.extension.onMessage.addListener()是很常用的content向background通信的手段，但在MV3中，需要改写为chrome.runtime.onMessage.addListener()

【报错】Refused to execute inline script because it violates the following Content Security Policy directive: “script-src ‘self’ ‘wasm-unsafe-eval’”. Either the ‘unsafe-inline’ keyword, a hash (‘sha256-Rltx/b//LIKPauTaz2gv4cpsZ0YVU5h3PTnfuiTtV/U=’), or a nonce (‘nonce-…’) is required to enable inline execution.
【解决】MV3不允许注入动态脚本，如果要运行动态脚本，可以让受信任的静态脚本获取远程脚本实现，注意引入的js文件需要加入web_accessible_resources获取权限，详见问题三

function nullThrows(v) {
    if (!v) {
        throw new Error("It's null")
    }
    return v
}

function active() {
    const mockDataNode = document.getElementById('banner-active');
    if (mockDataNode) {
    return null;
    }
    const myScript = document.createElement('script');
    myScript.src = chrome.runtime.getURL('static/js/active.js');
    myScript.id = 'banner-active';
    myScript.onload = function () {
        console.log("active script injected");
        this.remove();
    };
    nullThrows(document.body || document.documentElement).appendChild(myScript);
}

【报错】Denying load of chrome-extension://ddoklifpkebknaekabdfkgmleofcbihn/static/js/inject.js. Resources must be listed in the web_accessible_resources manifest key in order to be loaded by pages outside the extension.
【解决】引入的js没有执行权限，将需要插入目标页面的js加入web_accessible_resources中

"web_accessible_resources": [
    {
        "resources": [
            "/static/js/*.js"
        ],
        "matches": [
            "<all_urls>"
        ],
        "extension_ids": []
    }
],