error message with local storage

[anastasia_1]

Hello everyone, i am creating a website where i need to store some data from the signup form in some arrays(i need them for the login form, to check if the specific person has already an account). I need to store only the data from a few people as the website is just for simulation. So i tried local storage but the following message shows up every time: JSON.parse: unexpected character at line 1 column 1 of the JSON data(running in firefox browser) and Uncaught SyntaxError: Unexpected token u(running in chrome browser). Thanks in advance :) My code is:

var people= [];
var passwords= [];

function loginbutton(){ //onclick function in login form
    var usnm = document.getElementById("username").value;
    var pswd = document.getElementById("password").value;
    var op=localStorage.getItem('peoplenames');
    var op1=JSON.parse(op);

    for(var i = 0; i < op1.length; i++) {
      if(usnm===op1[i]){
          alert("user found");}
      else{
       alert("no user with that username");}      
    }
  }


function submitSignUp(){ //onclick function in sign up form

        var user = signupform.elements["username"].value;
        var pass = signupform.elements["password"].value;       

        people[people.length]=user;
        passwords[passwords.length]=pass;

        localStorage.setItem( 'peoplenames', JSON.stringify(people[people.length]));
        localStorage.setItem( 'passwords', JSON.stringify(passwords[passwords.length]));    
    }