function checkContactForm(submitbutton)
{
  var result = true;

  if (document.getElementById('firstname').value == '')
  {
		showErrorMessage(0);
    document.getElementById('firstname').focus();
    result = false;
  }

  if (result && document.getElementById('surname').value == '')
  {
		showErrorMessage(1);
    document.getElementById('surname').focus();
    result = false;
  }

  if (result && document.getElementById('email').value == '')
  {
		showErrorMessage(2);
    document.getElementById('email').focus();
    result = false;
  }

  if (result && (submitbutton !== false))
  {
    document.getElementById(submitbutton).disabled = true;
  }

  return result;
}

function enterField(element)
{
  document.getElementById(element).style.backgroundColor="#ffffff";
}

function leaveField(element)
{
  document.getElementById(element).style.backgroundColor="#f9f9f9";
}

function showErrorMessage(msg_num)
{
	var lang = document.getElementById('lang').value;
	var lang_index = 0;
	
	switch (lang)
	{
		case 'en':
		{
			lang_index = 1;
			break;
		}
	  case 'fr':
	  {
			lang_index = 2;
			break;
  	}
	}

	var messages = new Array();
	
	messages[0] = new Array();
	messages[0][0] = 'Bitte geben Sie Ihren Vornamen an!';
	messages[0][1] = 'Bitte geben Sie Ihren Nachnamen an!';
	messages[0][2] = 'Bitte geben Sie Ihre E-Mailadresse an!';
	messages[1] = new Array();
	messages[1][0] = 'Please fill in your first name!';
	messages[1][1] = 'Please fill in your surname!';
	messages[1][2] = 'Please fill in your email address!';
	messages[2] = new Array();
	messages[2][0] = 'Veuillez indiquer votre prénom!';
	messages[2][1] = 'Veuillez indiquer votre nom!';
	messages[2][2] = 'Veuillez indiquer votre adresse e-mail!';

	var message = messages[lang_index][msg_num];
	
	alert (message);
}