PROBLEM
Inpect this code! http://2018shell1.picoctf.com:56252 (link)
HINT
How do you inspect a website's code on a browser?
Check all the website code.
SOLUTION
Open networks tab(F12 in firefox) and there you'll see all the request. Read the response of every request and there you'll find the flag.
FLAG - picoCTF{ur_4_real_1nspect0r_g4dget_9dd3b33c}