//klasa walidator
Walidator = function(){
  this.czyWypelnione = function(id,komunikat){
    var el = document.getElementById(id);
    var er = document.getElementById(id + 'ERR');
    
    if(!el.value){
      er.innerHTML=komunikat;
      return false;
    }
    else return true;
  }
  
  this.czyPoprawnyMail = function(id,komunikat){
    var el = document.getElementById(id);
    var er = document.getElementById(id + 'ERR');
    var check = /^[a-zA-Z0-9._-]+@([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,4}$/;

    if(!check.test(el.value)){
      er.innerHTML=komunikat;
      return false;
    }
    else return true;
  }
  
  this.czyCyfra =  function(id){
    var check = /^[0-9]+$/;
    var er = document.getElementById('er'+id);
    var el = document.getElementById(id);
    if(check.test(el.value)){
      er.style.display='none';
    }
    else{
      er.style.display='inline-block';
    }
  }
  
  this.zeruj = function(id){
    var el = document.getElementById(id);
    var er = document.getElementById(id + 'ERR');
    
    if(el.value){
      er.innerHTML='';
    } 
  }
}
//end klasa walidator
walidator = new Walidator();