var port = null;
function setPort() {
    chrome.tabs.query({active: true, currentWindow: true}, function (tabs) {
        port = chrome.tabs.connect(tabs[0].id, {name: "CONTENTSCRIPT"});
    });
}

// when i click on something, get the port and send a message
function clickHandler(e) {
    setPort();
    if (port) {
        port.postMessage({key: 'message', value: true});
    }
}

chrome.runtime.onConnect.addListener(function (port) {
    if (port.name == "CONTENTSCRIPT") {
        port.onMessage.addListener(function (msg) {
            console.log(msg);
        });
    }
});

function setPort(callback) {
    chrome.tabs.query({active: true, currentWindow: true}, function (tabs) {
        port = chrome.tabs.connect(tabs[0].id, {name: "CONTENTSCRIPT"});
        callback(port);
    });
}

function clickHandler(e) {
    setPort( function (port) {
        if (port) { port.postMessage({key: 'message', value: true}); }
    });
}