options.js

function $(id) {
    return document.getElementById(id);
}

var computerName = localStorage.computerName;
if (computerName != null) $("computerName").value = computerName;

function saveComputerName() {
    if ($("computerName").value != "") {
        $("errorMsg").innerHTML = "";
        setTimeout(function () {
            try {
                var currentComputerName = $("computerName").value;
                chrome.storage.sync.get(function (items) {
                    var computersList = items["computers"];
                    if (!computersList) {
                        computersList = [];
                        items["computers"] = computersList;
                    }
                    var computersMap = {};
                    for (var i = 0; i < computersList.length; i++) {
                        var computer = computersList[i];
                        computersMap[computer] = true;
                    }
                    if (!computersMap[currentComputerName]) {
                        localStorage.computerName = currentComputerName;
                        computersList.push(localStorage.computerName);
                        chrome.storage.sync.set(items);
                        $("content").innerHTML = "From now your computer should be visible in other Chrome2Chrome as <b>" + localStorage.computerName + "</b>";
                    } else {
                        $("errorMsg").innerHTML = "Sorry, name " + currentComputerName + " was already used... choose different name";
                    }

                });
            } catch (e) {
                console.log(e);
                alert(e);
            }
        }, 0);
    }
}

$("saveComputerName").onclick = saveComputerName;
$("computerName").focus();