When I put the code into a JS interpreter it shows an error, as shown below:

var win = window.open('about:blank') 
      ^

ReferenceError: window is not defined
    at Object.<anonymous> (/tmp/judge/main.js:1:11)
    at Module._compile (internal/modules/cjs/loader.js:999:30)
    at Object.Module._extensions..js     (internal/modules/cjs/loader.js:1027:10)
    at Module.load (internal/modules/cjs/loader.js:863:32)
    at Function.Module._load     (internal/modules/cjs/loader.js:708:14)
    at Function.executeUserEntryPoint [as runMain]     (internal/modules/run_main.js: