循环不会在数组的对象上运行

Question

我使用JavaScript DOM制作了一个注册/登录系统 每当有人注册要使用uName和uPassword键添加对象时，我都会告诉它 到一个数组。 它添加了它，并在console.log中添加了3个对象。 它们的键值不同。

但是当我“登录”时，它仅用于数组中的第一个对象。

代码：

var regFlag = true;

var userNameLog = document.getElementById('logUserName');
var userPassLog = document.getElementById('logUserPass');


function loggedIn() {
  console.log('into log !');
  console.log(userNameLog.value);
  console.log(userPassLog.value);

  console.log(localStorage.getItem('usersArray'));
  var backToArr = JSON.parse(localStorage.getItem('usersArray'));
  console.log(backToArr);

  if (userNameLog.value != '' && userPassLog.value != '') {
    for (var i = 0; i < backToArr.length; i++) {
      console.log(backToArr[i]);
      for (var key in backToArr[i]) {
        console.log(key);
        if (backToArr[i].uName == userNameLog.value && backToArr[i].uPassword == userPassLog.value) {

          console.log('into successful login');
          document.getElementById('inputAnswer').removeAttribute('disabled');
          document.getElementById('subLogBtn').setAttribute('data-dismiss', 'modal');

        } else {
          document.getElementById('logMsgUser').innerHTML = '<p>השם משתמש או הסיסמא לא נכונים</p>';
          userNameLog.value = '';
          userPassLog.value = '';
        }
      }
    }
  } else {
    document.getElementById('logMsgUser').innerHTML = '<p>השם משתמש או הסיסמא לא נכונים</p>';
  }
}

/* end of login disaple or not */


function showRegister() {
  document.getElementById('logInForm').style.display = 'none';
  document.getElementById('regForm').style.display = 'block';
}


var userName = document.getElementById('regUserName');
var userPass = document.getElementById('regUserPass');
var userPassVali = document.getElementById('regUserPassVali');

function register() {



  console.log(userName.value);
  console.log(userPass.value);
  console.log(userPassVali.value);

  if (userPassVali.value != userPass.value) {
    document.getElementById('signUpMsg').innerHTML = '<p>סיסמאות לא תואמות</p>';
  } else {

    var usersObj = {
      uName: userName.value,
      uPassword: userPass.value
    }

    usersArr.push(usersObj);

  }

  var strUserArr = JSON.stringify(usersArr);

  console.log(strUserArr);

  if (typeof(Storage) != undefined) {

    localStorage.setItem('usersArray', strUserArr)

  }


  // console.log(localStorage);

  console.log(usersArr);
  console.log(usersArr.length)

  console.log(usersObj);

  // console.log(usersObj.uName)


}

<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModalCenter" id="modBtn">
                        התחברות/הרשמה
                    </button>

<!-- Modal -->
<div class="modal fade" id="exampleModalCenter" tabindex="-1" role="dialog" aria-labelledby="exampleModalCenterTitle" aria-hidden="true">
  <div class="modal-dialog modal-dialog-centered" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalCenterTitle">Modal title</h5>
      </div>
      <div class="modal-body">
        <form id="logInForm">
          <div class="form-group">
            <input type="text" id="logUserName" placeholder="Username">
            <input type="text" id="logUserPass" placeholder="Password">
            <div id="logMsgUser"></div>
            <a href="#" role="button" class="btn btn-secondary popover-test" title="Popover title" data-content="Popover body content is set in this attribute." id="subLogBtn">שלח</a>
          </div>
        </form>


        <form id="regForm">
          <div class="form-group">
            <input type="text" id="regUserName" placeholder="Username">
            <input type="text" id="regUserPass" placeholder="Password">
            <input type="text" id="regUserPassVali" placeholder="Validate Password">
            <div id="signUpMsg"></div>
            <a href="#" role="button" class="btn btn-secondary popover-test" title="Popover title" data-content="Popover body content is set in this attribute." id="subRegBtn">שלח</a>

          </div>
        </form>


      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" id="registerBtn">הירשם</button>
        <button type="button" class="btn btn-primary" id="logBtn">התחבר</button>
      </div>
    </div>
  </div>
</div>
</div>