Javascript：循环结束后的警报消息

Posted 2021-04-01

这是一个简单的学校登录练习。这是为了给你3次登录尝试。我想在循环停止后（使用三次尝试）这样做，它会提醒用户他没有剩余的尝试，他的帐户将被阻止。

就像是：

alert("You don't have any attempts left. Your account is now blocked);

这是我制作的循环：

var tries;

for (tries = 2; tries !== -1; tries--) {
    let User = prompt("Enter your username:");
    let Pass = prompt("Enter your password:");
        if (User === "hello" && Pass === "world") {
            alert("Welcome.");
            break;
        } else {
            alert("Incorrect username and/or password. You have " + tries + " attempt(s) left.");
        }
}

提前致谢。

答案

你在哪里非常接近。我想这就是你想要的。

var tries;

for (tries = 2; tries >= 0; tries--) {
    let User = prompt("Enter your username:");
    let Pass = prompt("Enter your password:");
        if (User === "hello" && Pass === "world") {
            alert("Welcome.");
            break;
        } else if (tries == 0) {
            alert("You don't have any attempts left. Your account is now blocked");
        }  else {
            alert("Incorrect username and/or password. You have " + tries + " attempt(s) left.");
        }
}

另一答案

你可以递归地实现这一点。每次输入错误的用户名或密码时，只需减少尝试次数。

var TRIES = 3;

function ask() {
  let User = prompt("Enter your username:");
  let Pass = prompt("Enter your password:");

  if (User === "hello" && Pass === "world") {
    return alert("Welcome.");
  }

  if (TRIES > 0) {
    alert("Incorrect username and/or password. You have " + TRIES + " attempt(s) left.");
    TRIES -= 1;
    ask()
  } else {
    alert("You don't have any attempts left. Your account is now blocked");
  }
}

ask()

另一答案

var tries;

for (tries = 0; tries < 3; tries++) {
    let User = prompt("Enter your username:");
    let Pass = prompt("Enter your password:");
        if (User === "hello" && Pass === "world") {
            alert("Welcome.");
            break;
        } else {
            alert("Incorrect username and/or password. You have " + tries + " attempt(s) left.");
        }
        if(tries == 2)
        {
            alert("You don't have any attempts left. Your account is now blocked);
        }
}

另一答案

let tries = 0;
for (tries = 3; tries-->0;) {
    let User = prompt("Enter your username:");
    let Pass = prompt("Enter your password:");
    if (User === "hello" && Pass === "world") {
        break;
    } 
    if (tries>0) {
       alert("Incorrect username and/or password. You have " + tries + " attempt(s) left.");
    }
}
if (tries<0) {
    alert("You don't have any attempts left. Your account is now blocked");
} else {
    alert("Welcome.");
}

另一答案

也许您可以通过执行以下操作来实现此目的：

for (var attemptsRemaining = 3; attemptsRemaining > 0; attemptsRemaining--) {
  
    let User = prompt("Enter your username:");
    let Pass = prompt("Enter your password:");
  
    if (User === "hello" && Pass === "world") {        
      alert("Welcome.");
      break;
    
    } else if(attemptsRemaining <= 1) {          
      alert("To many failed attempts. Your account is now blocked.");
    }
    else {    
      alert("Incorrect username and/or password. You have " + (attemptsRemaining - 1) + " attempt(s) left."); 
    }
  }
}

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