inject.js

if (location.href == 'https://api.twitter.com/oauth/authorize') {
    var meta = $('meta[http-equiv="refresh"]');
    meta.attr('content', meta.attr('content').replace('twittersdk', 'app'));
} else if (location.host == "www.periscope.tv") {
    if (!Array.prototype.findIndex) {
        Array.prototype.findIndex = function (predicate) {
            if (this == null) {
                throw new TypeError('Array.prototype.findIndex called on null or undefined');
            }
            if (typeof predicate !== 'function') {
                throw new TypeError('predicate must be a function');
            }
            var list = Object(this);
            var length = list.length >>> 0;
            var thisArg = arguments[1];
            var value;

            for (var i = 0; i < length; i++) {
                value = list[i];
                if (predicate.call(thisArg, value, i, list)) {
                    return i;
                }
            }
            return -1;
        };
    }
}