popup.js

function save() {
    chrome.tabs.create({"url": chrome.extension.getURL("popup/output.html")}, onCreated);
}

function onCreated(newTab) {
    chrome.tabs.executeScript(newTab.id, {
        //file: "popup/output.js",
        code: "alert('hello');",
        //runAt: "document_start"
        //allFrames: true
    }, onExecuted);
}

function onExecuted(result) {
  alert("inside onExecuted");
}