picoCTF Writeup picoGym Practice Challenges login (注意<spoiler>)

login

Description
My dog-sitter's brother made this website but I can't get in; can you help?
login.mars.picoctf.net

index.js

(async()=>{
    await new Promise((e=>window.addEventListener("load", e))),
    document.querySelector("form").addEventListener("submit", (e=>{
        e.preventDefault();
        const r = {
            u: "input[name=username]",
            p: "input[name=password]"
        }
          , t = {};
        for (const e in r)
            t[e] = btoa(document.querySelector(r[e]).value).replace(/=/g, "");
        return "YWRtaW4" !== t.u ? alert("Incorrect Username") : "cGljb0NURns1M3J2M3JfNTNydjNyXzUzcnYzcl81M3J2M3JfNTNydjNyfQ" !== t.p ? alert("Incorrect Password") : void alert(`Correct Password! Your flag is ${atob(t.p)}.`)
    }
    ))
}
)();

YWRtaW4 はBASE64でデコードした場合adminとなる。
cGljb0NURns1M3J2M3JfNTNydjNyXzUzcnYzcl81M3J2M3JfNTNydjNyfQは
picoCTF{53rv3r_53rv3r_53rv3r_53rv3r_53rv3r}