javascript获取返回当前 URL 的协议

    (function () {
        var bp = document.createElement('script');
        var curProtocol = window.location.protocol.split(':')[0];
        console.log(curProtocol);
        if (curProtocol === 'https') {
            bp.src = 'https://v1.qiaodu.net/push.js';
        }
        else {
            bp.src = 'http://v1.qiaodu.net/push.js';
        }
        var s = document.getElementsByTagName("script")[0];
        s.parentNode.insertBefore(bp, s);
    })();