PairDrop/app/elements/p2p-network/tab-active.html

<script>
'use strict';
var vis = (function() {
    var stateKey,
        eventKey,
        keys = {
            hidden: "visibilitychange",
            webkitHidden: "webkitvisibilitychange",
            mozHidden: "mozvisibilitychange",
            msHidden: "msvisibilitychange"
        };
    for (stateKey in keys) {
        if (stateKey in document) {
            eventKey = keys[stateKey];
            break;
        }
    }
    return function(c) {
        if (c) {
            document.addEventListener(eventKey, c);
        }
        return !document[stateKey];
    };
})();
</script>