javascript - 这种类型的JS加密怎么破解？

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</code>

回复内容：

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</code>

这种简单的东西压根起不到加密的效果，骗骗小孩罢了。
原理上无非就是将JS代码作为字符串，对这个字符串进行escape一类的混淆，执行时不过unescape再eval一下。

<code>this.eval=function (s) {
  console.log(s);
};
</code>

这样不就能得到原来的代码了么：

<code>var fangke_xHead = document.getElementsByTagName('HEAD').item(0);
var para = document.getElementById("qq_js");
var v;
var v = para.src;
var tmp = v.split("?");
var ids = tmp[1];
var url = tmp[0].split("Count.js");

function skip() {
    if (document.getElementById('QQfangke_iframe') == null) {
        var QQfangke_xurl = 'http://qq-812631263.huantu.net/T-census.php?' + ids;
        var QQfangke_ref = encodeURIComponent(document.referrer);
        var QQfangke_page = encodeURIComponent(document.location.href);
        var QQfangke_url = QQfangke_xurl + '&url=' + url[0] + '&llurl=' + QQfangke_ref + '&thepage=' + QQfangke_page + '&t=' + new Date().getTime();
        var iframe = document.createElement("iframe");
        iframe.src = QQfangke_url;
        iframe.id = "QQfangke_iframe";
        iframe.name = "QQfangke_iframe";
        iframe.style.width = "0px";
        iframe.style.height = "0px";
        iframe.scrolling = "no";
        iframe.setAttribute('frameborder', '0', 0);
        document.body.appendChild(iframe)
    }
}
skip();
</code>

---

举一隅不以三隅反，则免不了调试代码通宵～
我没有明说的是，它的代码进行了好几次的解码，所以原代码第一次运行时，eval方法截获的字符串仍然是一个"eval(SubstantialCode)"形式的字符串，所以需要将其中SubstantialCode再执行一次，反复此方法，最终eval会截获到原始的代码。
大致这样吧：

<code>var _eval=this.eval;
this.eval=function (s) {
  if (s.indexOf("eval")==0) 
    _eval(s);
  else 
    console.log(s);
};
</code>