break和continue

break语句可立即退出循环

continue 结束本次循环，继续开始下一次循环

var pwd,pwdAgain;
    while(true){
        pwd = prompt('请输入密码');
        if(pwd=='123456'){
           pwdAgain=prompt("请再次输入密码");
           if(pwdAgain==pwd){
               break;
           }else{
               continue;
           }
        }
     }