Question

当尝试在我的网站上创建受密码保护的按钮时，错误：'（'预期。给出的所有其他问题都被证明是无用的（我是javascript的初学者，因此如果答案很明显，请原谅我）

function passWord2
var askaccess = 1();
var pass1 = prompt('Please Enter Password To Access Page', ' ');
while (askaccess < 3) {
  if (!pass1)
    history.go(-1);
  if (pass1.toLowerCase() == "gimmethedeets") {
    alert('Password Correct');
    window.open('logslist.html');
    break;
  }
  askaccess += 1;
  var pass1 =
    prompt('Password Incorrect.', 'Password');
}
if (pass1.toLowerCase() != "password" & askaccess == 3)
  history.go(-1);
return " ";

Answer 1

这里可能还有个问题，但是一个函数具有function functionname(variablename){}签名。

这些都不是安全的密码输入，用户可以轻松查看/猜测。

function passWord2() {
  var askaccess = 1();
  var pass1 = prompt('Please Enter Password To Access Page', ' ');
  while (askaccess < 3) {
    if (!pass1)
      history.go(-1);
    if (pass1.toLowerCase() == "gimmethedeets") {
      alert('Password Correct');
      window.open('logslist.html');
      break;
    }
    askaccess += 1;
    var pass1 =
      prompt('Password Incorrect.', 'Password');
  }
  if (pass1.toLowerCase() != "password" & askaccess == 3)
    history.go(-1);
  return " ";
}

// call it
passWord2();

重写一些意图。在适当的地方发表评论

function checkForPassword() {
  // declare stuff, use let to keep block scope,
  // these have values here to not get reference error
  // not strickly needed but a good habit, 
  // when it gets a value read:
  // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let
  let entryAttempts = 1,
    entryValue = "",
    correctValue = "gimmethedeets";
  // this gives 2 attempts due to the 1 initial value and not 0
  while (entryAttempts < 3) {
    entryValue = prompt('Please Enter Password To Access Page', '');
    // check for null empty values 
    if (entryValue != null && entryValue.length > 0 && entryValue.trim() != "") {
      // I find this slightly more clear but same as  history.go(-1);
      window.history.back();
    }
    // value null if they hit cancel, protect from that
    if (entryValue != null && entryValue.toLowerCase() == correctValue) {
      alert('Password Correct');
      // open the new window, different than making THIS page go there as ino window.location ='logslist.html';
      window.open('logslist.html');
      break;
    }
    entryValue = prompt('Password Incorrect.', 'Password');
    entryAttempts += 1; // last in while loop
  }
  // slight restructure to make intent clear, fix bitwise & to to logical &&
  // a guess on the intent here
  if ((entryValue == null || entryValue.toLowerCase() != "password") && entryAttempts === 3) {
    history.back();
  } else {
    // to be clear if entry is "Password" it returns after 2 attempts
    return " ";
  }
}

// call it
let entry = checkForPassword();

当我尝试编译时，我的JavaScript代码给出了错误

1 个答案: