myXHRScript.js

/**
 * 重写ajax方法，以便在请求结束后通知content_script
 * inject_script无法直接与background通信，所以先传到content_script，再通过他传到background
 */
(function (xhr) {
  var XHR = xhr.prototype;
  var open = XHR.open;
  var send = XHR.send;

  // 对open进行patch 获取url和method
  XHR.open = function (method, url) {
    this._method = method;
    this._url = url;
    return open.apply(this, arguments);
  };
  // 同send进行patch 获取responseData.
  XHR.send = function (postData) {
    this.addEventListener('load', function () {
      if (this._url && this.responseType.length == 0) {
        try {
          let resJSONObj = JSON.parse(this.responseText);
          if (resJSONObj['isPage'] === true || this._url.includes('SketchJSON')) {
            // 因为inject_script不能直接向background传递消息, 所以先传递消息到content_script
            window.postMessage(resJSONObj, '*');
          }
        } catch (error) {

        }

      }
    });
    return send.apply(this, arguments);
  };
})(XMLHttpRequest);