How to decode a JSFuck script?

Question

I have this code in JavaScript:

[(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+
(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+
(!![]+[])[+!+[]]]

In the console, it will return

Array [ "filter" ]

And how can I decode a lot of text that’s similar to the text above? E.g.:

[][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+
(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]][([][(![]+[])[+[]]+
([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+
(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]]+[])[!+[]+!+[]+!+[]]+
(!![]+[][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+
(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]])[+!+[]+[+[]]]+
([][[]]+[])[+!+[]]+(![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+
(!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+
(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+
(!![]+[])[+!+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+
([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+
(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]])[+!+[]+[+[]]]+(!![]+[])[+!+[]]]

I want to see the plain script.

Answer 1

I have seen many decoding attempts around, but none that work reliably. The easiest way I have found to decode Non Alphanumeric Javascript is with Chrome.

Open Chrome > Go to jsfuck.com > paste the code you would like to decode in the window > hit Run This.

Then open the Console, in the case of your specific code from PasteBin there will be an error:

Uncaught TypeError: Cannot read property 'innerHTML' of null  

To the right of the error, click the line number link, and the code will be revealed. The result is:

(function(){
    window.false=document.getElementById('sc').innerHTML;
})

Which explains why you get the error trying to just decode it using JSFuck itself. There is no element with the id sc on their site.

Answer 2

You can use this website to decode jsfuck: http://codertab.com/jsunfuck

UPDATED I extracted the decode javascript from the URL above, this is how the decode process work: (javascript)

s = source.slice(0, source.length - 2); txtResult = eval(s);

Hope it help!

Answer 3

    let elem = yourJSFuck
function decode(elem) {
    return (/\n(.+)/.exec(eval(elem.replace(/\s+/, "").slice(0, -2)))[1]);
}

console.log(decode(elem))

This should work, the source is from this page