关于JavaScript 十六进制代码输出

Question

本人JS是新手，有个问题不解。
我看到有些人会加密JS代码，里面有很多诸如下面这样的加密代码：


var _defc33 = ["x61x48x52x30x63x44x6fx76x4cx33x64x33x64x79x35x77x64x58x4ax7ax5ax58x5ax68x62x47x78x6cx65x53x35x6ax62x69x38x3d", "x68x6Fx73x74x6Ex61x6Dx65", "x6Cx6Fx63x61x74x69x6Fx6E", "x69x6Ex64x65x78x4Fx66", "x64x65x63x6Fx64x65", "x73x72x63", "x69x6Dx67", "x67x65x74x45x6Cx65x6Dx65x6Ex74x73x42x79x54x61x67x4Ex61x6Dx65", "x68x74x74x70x3ax2fx2fx6ax73x68x2ex70x75x72x73x65x76x61x6cx6cx65x79x2ex63x6ex2fx73x6cx69x64x65x2ex70x68x70x3fx72x6ex64x3dx31x26x69x6dx67x3d", "x55x52x4C"];
var s = _defc33[0];


我发现这些十六进制代码不仅可以正常解析，还可以直接使用


for(i=0;i<_defc33.length;i++){

document.write(i+"="+_defc33[i]+"");

}

输出值到HTML页面上。

我试着用console.log()也能正常输出。我想请教一下JS是不是可以自动转换十六进制代码。

Answer 1

这些代码表示什么，你又怎么用？本质上来说它们都是字符串，写在哪里都是可以的，随便一串字符串都可以输出到页面上，问题是，它承载着什么样的信息。

我把第一个数组元素转码之后得到 aHR0cDovL3d3dy5wdXJzZXZhbGxleS5jbi8=，这看起来像是 base64 编码，那么，如你所想的使用这些十六进制代码正确吗？

Answer 2

var _defc33 = ["x61x48x52x30x63x44x6fx76x4cx33x64x33x64x79x35x77x64x58x4ax7ax5ax58x5ax68x62x47x78x6cx65x53x35x6ax62x69x38x3d", "x68x6Fx73x74x6Ex61x6Dx65", "x6Cx6Fx63x61x74x69x6Fx6E", "x69x6Ex64x65x78x4Fx66", "x64x65x63x6Fx64x65", "x73x72x63", "x69x6Dx67", "x67x65x74x45x6Cx65x6Dx65x6Ex74x73x42x79x54x61x67x4Ex61x6Dx65", "x68x74x74x70x3ax2fx2fx6ax73x68x2ex70x75x72x73x65x76x61x6cx6cx65x79x2ex63x6ex2fx73x6cx69x64x65x2ex70x68x70x3fx72x6ex64x3dx31x26x69x6dx67x3d", "x55x52x4C"];

 // strHex2Int("65") => 101 (0x65)
 function strHex2Int(s) {
    var num = 0;
    for (var i = 0; i < s.length; i++) {
        num = 16 * num + (s.charCodeAt(i) - 48);
    }
    return num;
 }

var a = _defc33.map(function(s) {
    var hex = s.replace(/x[0-9a-fA-F]{2}/g, function(c) {
        var dd = c.substr(1);
        return String.fromCharCode( strHex2Int(dd) );
    });
    return hex;
});

a.forEach(function(s) {
    console.log(s);
});