For testing, the code should be selected and copied directly from tweets . - approx. trans.

I recently found this tweet from <a href="https://twitter.com/FakeUnicode/"> @FakeUnicode < / a>. There was a JavaScript snippet that looked pretty innocuous, but displayed a hidden message. It took me some time to understand what was going on. I think that the record of the steps of my investigation may be of some interest to someone.

Here is the snippet:

image

What would you expect from him?

Here we use the for in loop, which passes through the enumerable properties of the object. Since only the property A is specified, we can assume that the message with the letter A will be shown. Well ... I was wrong. : D
KlauS 23 september 2017, 8:40