var login = document.getElementById('login_label');
if (login.offsetWidth == 0) {      
  document.login_form.login.onfocus = function() {
    document.login_form.login.className = 'filled';
  }
  document.login_form.login.onblur = function() {
    if (document.login_form.login.value == "") {
      document.login_form.login.className = 'empty';
    }
  }
}

var pwd = document.getElementById('pwd_label');
if (pwd.offsetWidth == 0) {
  document.login_form.password.onfocus = function() {
    document.login_form.password.className = 'filled';
  }
  document.login_form.password.onblur = function() {
    if (document.login_form.password.value == "") {
      document.login_form.password.className = 'empty';
    }
  }
}

document.login_form.password.focus();
document.login_form.login.focus();
document.login_form.login.blur();