From inspecting the code through developer tools of Chrome, we get a hint that it is using the socket library.

Here we noticed that the event "Victory" will print out flag


Going through the code we see another piece of code that broadcast event "movePlayer".


On Console tab of developer tool, we copy pasted and executed the code with random value for x and y. Then we tried it with values 1366, 768 since it represents top right corner of the screen and BINGO!! we got the flag.