http://freebitco.in/?r=462931 please use this referer address for registration thx
Choose Multiply BTC. press f12 in the browser chrome, insert the script and press enter.

var multiplyMyBTC = (function () {
 
        var randomString = function () {
                var charSet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
                var rString = '';
                for (var i = 0; i < 16; i++) {
                        var randomPoz = Math.floor(Math.random() * charSet.length);
                        rString += charSet.substring(randomPoz, randomPoz + 1);
                }
                return rString;
        };
 
        var balance = parseFloat($('#balance').html());
        var initialBet = 0.5 * balance / 100;
            initialBet = initialBet >= 0.00000001 ? initialBet : 0.00000001;
        var bet = initialBet;
        var client_seed = randomString();
        var multiplier = 2;
        var totalBTCTr = 0;
       
        window.multiplyBTC = true;
 
        window.toggleMultiplyBTC = function () {window.multiplyBTC = !window.multiplyBTC;};
 
        return function () {
                $.get('/?op=double_your_btc&m=' + ["hi", "lo"][Math.floor(Math.random() * 2)] + '&client_seed=' + client_seed + '&jackpot=0&stake=' + bet.toFixed(8) + '&multiplier=' + multiplier, function(data) {
                        var result = data.split(":");
                        if (result[0] == "s1") {
                                balance = parseFloat(result[3]);
                                if (result[1] == "w") {
                                        totalBTCTr += parseFloat(result[4]);
                                        console.log("+" + result[4] + " BTC, Total: " + totalBTCTr.toFixed(8));
                                        bet = initialBet;
                                } else if (result[1] == "l") {
                                        totalBTCTr -= parseFloat(result[4]);
                                        console.log("-" + result[4] + " BTC, Total: " + totalBTCTr.toFixed(8));
                                        if(bet * 4 < balance) {
                                                bet *= 2;
                                        } else {
                                                bet = initialBet;
                                        }
                                }
                       
                                $('#balance').html(result[3]);
                               
                                client_seed = randomString();
                                if(window.multiplyBTC) {
                                        multiplyMyBTC();
                                }
                        } else {
                                $('#double_your_btc_error').show();
                                BetErrors(result[0]);
                        }
                });
        }
})();
 
multiplyMyBTC();