onmessage = function (event) {
    var arguments = JSON.parse(event.data);
    run(arguments.start, arguments.end);
};
function run(start, end) {
    var n = start;

    while (n < end) {
        var k = Math.sqrt(n);
        var found = false;

        for (var i = 2; !found && i <= k; ++i) {
            found = n % i === 0;
        }

        if (!found) {
            postMessage(n.toString());
        }

        n++;
    }
}