html

<iframe id="kiwiIframe" v-if="showPickForm" src="${chrome.runtime.getURL("iframes/notSupport.html")}">

1.父页面向子页面传递值

          let kiwiIframe = document.querySelector("#kiwiIframe");
          kiwiIframe.contentWindow.postMessage("support_ok", "*");

2.子页面接受值

    window.addEventListener("message", function () {
      // console.log(event.data);
      switch (event.data) {
        case "support_ok":
                   console.log('????')
          break;
      }
    });

3.子页面再向父页面传递值

 window.parent.postMessage("support", "*");

4.父页面再次接受值

          window.addEventListener("message", function (event) {
            // console.log(event);
            switch (event.data) {
              case "support":
               console.log('?????')
                break;
            }
          });