let username = document.querySelector("#username");
let pwd1 = document.querySelector("#password");
let pwd2 = document.querySelector("#password-2");
let nameReg = /^\w{3,10}$/;
let nameIsLegal = nameReg.test(username.value);
let pwdReg = new RegExp("^.{6,20}$");
let pwdIsLegal = pwdReg.test(pwd1.value);
return nameIsLegal && pwdIsLegal && pwd1.value === pwd2.value;