Inspired by this tweeter post by Marcus Lagergren and the JS1K competition, here is a valid Javascript code snippet for you obfuscated code lovers:
ｰ=!+[]+!+[]+!+[]+!+[],ߺ=ｰ+ｰ,ǀ=ߺ+ߺ,ꓹ=!+[]+[],ǃ=!+[]+!+[]+!+[],ᚐ=ꓹ[+[]],ꓹ=ᚐ+ꓹ[ǃ]+(![]+[])[ǃ]+ᚐ,ᚐ=/,/[ꓹ]+[],ꓹ=ǀ+ߺ+!+[]+!+[],ꓹ=ᚐ[ǃ]+ᚐ[ｰ+!+[]+!+[]],ǃ=+[],ᚐ=+!+[],ǃ=ꓹ[ǃ]+ꓹ[ᚐ]+([][[]]+[])[ᚐ]+(![]+[])[!+[]+!+[]+ᚐ]+(!+[]+[])[ǃ]+(!+[]+[])[ᚐ]+([][[]]+[])[ǃ]+ꓹ[ǃ]+(!+[]+[])[ǃ]+ꓹ[ᚐ]+(!+[]+[])[ᚐ],ᚐ=ǃ[ǃ]+[],ǃ=!+[]+!+[],ꓹ=(!+[]+[])[+[]]+ꓹ[+!+[]]+ᚐ[ߺ+!+[]]+ᚐ[ߺ+ǃ]+ᚐ[ߺ+ǃ+!+[]]+ᚐ[ߺ+ｰ]+ᚐ[ߺ+ｰ+!+[]]+ᚐ[ߺ+ｰ+ǃ],ǃ=ǀ+ǀ+ｰ,(+[]+!+[]+!+[]+ｰ+ߺ)[ꓹ](ǃ)+(+[]+!+[]+!+[]+ｰ+ǀ)[ꓹ](ǃ)+(!+[]+!+[]+!+[]+ߺ)[ꓹ](ǃ)+(+[]+!+[]+!+[]+ߺ)[ꓹ](ǃ)+(+[]+!+[]+!+[]+ｰ+ߺ+ǀ)[ꓹ](ǃ)+(+[]+ｰ+ߺ)[ꓹ](ǃ)+(!+[]+ǀ)[ꓹ](ǃ)+(+[]+!+[]+!+[]+ｰ+ߺ)[ꓹ](ǃ)+(!+[]+!+[]+!+[]+ǀ+ǀ)[ꓹ](ǃ)+ᚐ[ߺ]+(+[]+!+[]+!+[]+ｰ+ǀ)[ꓹ](ǃ)+(+[]+ߺ+ǀ)[ꓹ](ǃ)+(+[]+!+[]+!+[]+ǀ)[ꓹ](ǃ)+ᚐ[ߺ]+(+[]+ߺ)+ᚐ[ǀ]
Just click here to check on http://repl.it what this snippet evaluates to.
This snippet has been generated by an home-made algorithm, whose goal is to produce Javascript code containing ZERO character, that outputs a string when evaluated. Maybe not very useful, but it's a kind of constrained code writing I guess :) I won't reveal all the tricks I used here, maybe in a later post. There is another one for you:
ｰ=!+[]+!+[]+!+[]+!+[],ߺ=ｰ+ｰ,ǀ=ߺ+ߺ,ꓹ=!+[]+[],ǃ=!+[]+!+[]+!+[],ᚐ=ꓹ[+[]],ꓹ=ᚐ+ꓹ[ǃ]+(![]+[])[ǃ]+ᚐ,ᚐ=/,/[ꓹ]+[],ꓹ=ǀ+ߺ+!+[]+!+[],ꓹ=ᚐ[ǃ]+ᚐ[ｰ+!+[]+!+[]],ǃ=+[],ᚐ=+!+[],ǃ=ꓹ[ǃ]+ꓹ[ᚐ]+([][[]]+[])[ᚐ]+(![]+[])[!+[]+!+[]+ᚐ]+(!+[]+[])[ǃ]+(!+[]+[])[ᚐ]+([][[]]+[])[ǃ]+ꓹ[ǃ]+(!+[]+[])[ǃ]+ꓹ[ᚐ]+(!+[]+[])[ᚐ],ᚐ=ǃ[ǃ]+[],ǃ=!+[]+!+[],ꓹ=(!+[]+[])[+[]]+ꓹ[+!+[]]+ᚐ[ߺ+!+[]]+ᚐ[ߺ+ǃ]+ᚐ[ߺ+ǃ+!+[]]+ᚐ[ߺ+ｰ]+ᚐ[ߺ+ｰ+!+[]]+ᚐ[ߺ+ｰ+ǃ],ǃ=ǀ+ǀ+ｰ,(!+[]+ǀ)[ꓹ](ǃ)+(!+[]+!+[]+ｰ+ߺ)[ꓹ](ǃ)+(!+[]+ｰ+ǀ)[ꓹ](ǃ)+(!+[]+ｰ+ǀ)[ꓹ](ǃ)+(ߺ+ǀ)[ꓹ](ǃ)+ᚐ[ߺ]+(ǀ+ǀ)[ꓹ](ǃ)+(ߺ+ǀ)[ꓹ](ǃ)+(!+[]+!+[]+!+[]+ߺ+ǀ)[ꓹ](ǃ)+(!+[]+ｰ+ǀ)[ꓹ](ǃ)+(!+[]+ｰ+ߺ)[ꓹ](ǃ)
Again, click here to check its execution on http://repl.it
EDIT [26/11/2014] : Actually, I found out this is not breaking ground at all, there are actually plenty of similar crazy "NoAlnum" hacks & contests : http://security.stackexchange.com/a/8265. Thanks to Thibault for finding out !
Now, the commented source code of my own generic ASCII-to-NoAlnum translator can be found on GitHub.
EDIT[19/12/2014] : there is an equivalent one for Python : http://benkurtovic.com/2014/06/01/obfuscating-hello-world.html
EDIT[3/03/2016] : funnily, the recent vulnerability Ebay has been exposed to relies on the very same trick, except that with JSFuck or hieroglyphy you only need 6 non-alphanumeric characters !
EDIT[27/11/2017] : more creative coding : http://aem1k.com
