花钱买到的技术,chrome扩展 内容页获取原始页面的js变量

1 内容页往原始页面新加脚本,目的是接受来自内容页的消息,并返回js变量

var myScript = document.createElement("script");
myScript.append('window.addEventListener("message", async function(event) { if (event.data.from === "extenstion") { var data = await new Promise(function(resolve) { resolve(window.wx.cgiData); });var message = { "from": "web", "to": "extenstion", "data": window.wx.cgiData };window.postMessage(message, "*"); }});');
document.body.append(myScript);

其中附加的代码格式化后如下

window.addEventListener("message", async function(event) {
    if (event.data.from === "extenstion") {
        var data = await new Promise(function(resolve) {
            resolve(window.wx.cgiData);
        });
        var message = {
            "from": "web",
            "to": "extenstion",
            "data": window.wx.cgiData
        };
        window.postMessage(message, "*");
    }
});

收到来自内容页的消息后,返回指定js变量

2 内容页新加监听,接受来自原始页的消息

window.addEventListener("message", function(event) {
    if (event.data.from === "web") {
        console.log("cgiData", event.data.data);
    }
});

3 给原始页发消息

var message = { "from": "extenstion", "to":"web", "data": "test" };
window.postMessage(message, "*");