Below this is my code main.html

<form action="#" class="signForm">
  <input type="text" placeholder="Ваш Email..." class="loginSign">
  <div class="group">
    <input name="PassSign" type="password" placeholder="Пароль" class="passSign">
    <i class="fas fa-eye show__pass"></i>
  </div>
  <div class="btn signBtn">Войти</div>
</form>
      
   

this is my code main.js

const loginSign = document.querySelector('.loginSign')
const passSign = document.querySelector('.passSign')
const signBtn = document.querySelector('.signBtn')

var login = false;
async function getUser() {
    const data = await getData()

    data.forEach((user,index)=> {
        
        if(user.login.toLowerCase() === loginSign.value.toLowerCase() & user.pass.toLowerCase() === passSign.value.toLowerCase()) {
            login = true
        }
    });

    if(login) {
        setTimeout(function(){
            successful.classList.add('active')
        },500)
        setTimeout(function(){
            successful.classList.remove('active')
        },3000)
        console.log(login)
    }
    else {
        unsuccessful.classList.add('active')
        setTimeout(function() {
            unsuccessful.classList.remove('active')
        },2000)
        console.log("err :" + login)
    }
}

The main problem is when I am uploading page and and sign in. It works. When I'm entering next username and password (wrong). It works. How to remove old username and password ?