demo.html

<html>
<script type="text/javascript" src="crypto-js.js"></script>
<script>
    var burl = 'https://api.binance.com';
    var endPoint = '/sapi/v1/broker/subAccount';
    var dataQueryString = "recvWindow=20000&timestamp=" + Date.now();


    var keys = {
        'akey': '',
        'skey': ''
    }

    var signature = CryptoJS.HmacSHA256(dataQueryString, keys['skey']).toString(CryptoJS.enc.Hex);

    var ourRequest = new XMLHttpRequest();

    var url = burl + endPoint + '?' + dataQueryString + '&signature=' + signature;

    var ourRequest = new XMLHttpRequest();

    ourRequest.open('POST', url, true);
    ourRequest.setRequestHeader('X-MBX-APIKEY', keys['akey']);

    ourRequest.onload = function () {
        console.log(ourRequest.responseText);
    }
    ourRequest.send();
</script>

</html>