function validate(){
var username = document.getElementById("username").value;
var password = document.getElementById("password").value;

  for(var p in retrievedusers){
      console.log(p+':'+retrievedusers[p].username+'|'+retrievedusers[p].email);
      if(username==retrievedusers[p].username && password==retrievedusers[p].password){
      alert("Logged in successfully");
      }
  }
}