python执行“古怪的”js代码问题

本文主要是介绍python执行“古怪的”js代码问题，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

因工作需要，碰见了这样的js代码，以前没见过，所以没见识的觉得“古怪”：

!+[]+!+[]+!+[]+!+[]

在chrome的console中输入可以得到：

这样一串的“![]+”竟然可以表示一个数字！非前端人员表示好厉害。。。。。。

然后简单说一下用python如何执行该js代码，因为需要，我使用的是Python的ghost模块，简单的代码实现如下：

import ghost
gh = ghost.Ghost()
se = ghost.Session(gh)
se.evaluate('!+[]+!+[]+!+[]+!+[]')

输出结果：

(4.0, [])

如果仅仅是上面的“!+[]+!+[]+!+[]+!+[]”还是比较好解决的，但是遇见如此长的一串js，在使用ghost解析的时候缺报错了，js代码的一部分如下：

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直接使用ghost解析报错如下：

[WARNING ] Ghost<203fdc72-f38e-4fb8-854c-c8d2c91214da>: undefined(1): SecurityError: DOM Exception 18: An attempt was made to break through the security policy of the user agent.

经分析，是因为上面的js代码还原后，会对当前的document对象执行一些操作，但是当前的ghost对象没有加载过任何HTML文档，所以本身没有任何document对象可以被操作。所以，解决办法为，在使用ghost解析js之前，先让ghost打开一个可以正常访问的url，例如：https://www.baidu.com/，过程截图如下：