When the extension is installed, the extension will create a listener listening to the request to get history search result. Since the history api has to be called in the background.js, I have to use message passing to send the history query result from backend to the popup window. Since I cannot get the url of the current activating page, I have to inject a listener to the visited page when the plugin loads so that the popup window can send the request to the visited page to get the visiting url. When the popup window is loaded, it will first sent a request to the visited page to get the visiting url, then it will send a request to the backend to get the history search result. Once the data are ready, a eChart line chart will be initialized and shown in the popup window.