how to validate user login using javascript and nedb

Please help me, with the code below. am trying to validate login using javascript and nedb database. what am i do wrong.

login.html

 <form name="login" onSubmit="return validateForm();" action="home.html" method="post">

  <input type="text" name="user" id="user" placeholder=" Enter Username" required/>
     <br>
  <input type="password" name="pass" id="pass" placeholder="Enter Password" required/>
  <input type="submit" value="Login">

 </form>

loginvalidate.js

This code is meant to validate, check and query the database for the username and password but it doesn't. it proceed to the home.html after ok is clicked when the dialog appears.

  const database = require('../scripts/logindb');


    function validateForm() {
    var user = document.loginform.user.value;
    var pass = document.loginform.pass.value;

     database.getAdmin(function(admin){

    var username = admin.username; 
    var password = admin.password;
    if ((user == username) && (pass == password)) {
        return false;
    }
    else {
        alert ("Error , please check your username and password");
        return false;
    }

     });        
}

logindb.js

var Datastore = require('nedb');

db = new Datastore({ filename: 'db/admin.db', autoload: true });

exports.addAdmin = function(firstname, lastname, username, password) 

{

var admin = {
        "firstname": firstname,
        "lastname": lastname,
        "username": username,
        "password": password
    };

db.insert(admin, function(err, newDoc) {

        if (err) throw err;
        console.log("Table created!");
        db.close();

 });

 };

exports.getAdmin = function(fnc) {

    db.find({}, function(err, docs) {
        fnc(docs);

  });
}

via Manuel