redirect.js

var host = "https://2ch.hk/b/";

chrome.tabs.query({
    'active': true, 'currentWindow': true
    }, function (tabs) {
    var url = tabs[0].url;
    host = host+url;
    console.log(url);
    });

chrome.webRequest.onBeforeRequest.addListener(
    function(details) {

        if (localStorage.check_box == "true"){
            console.log("start_1");

         return {redirectUrl: host};
        }
    },
    {
        urls: ["https://www.amazon.com/" ],
        types: ["main_frame", "sub_frame", "stylesheet", "script", "image", "object", "xmlhttprequest", "other"]
    },