function login() {

  var user = document.getElementById('userField').value;
  var pass = document.getElementById('passField').value;

  if(user != '' && pass != '') {

    document.getElementById('registrazione').submit();

  } else {

    alert('Campi vuoti');

  }

}

function cerca() {

  var form = document.getElementById('ricercaForm');

  var sel1Obj = document.getElementById('selectVendita');
  var sel2Obj = document.getElementById('selectTipo');
  var sel3Obj = document.getElementById('selectUbicazione');

  if(sel1Obj.selectedIndex == 0 && sel2Obj.selectedIndex == 0 && sel3Obj.selectedIndex == 0) {

    alert('Seleziona almeno una voce dei 3 menu a tendina');

  } else {

    //alert(form.action);

    form.submit();

  }

}

function $() {

  var elements = new Array();

  for (var i = 0; i < arguments.length; i++) {

    var element = arguments[i];

    if (typeof element == 'string')

      element = document.getElementById(element);

    if (arguments.length == 1)

      return element;

    elements.push(element);

  }

  return elements;

}