function clearBox(box) {
  box.value = '';
  box.onfocus = null;
}

function toggleContactVisibility() {
  var target = document.getElementById('contact');
  
  if(target.style.display != 'block') {
    target.style.display = 'block';
  } else {
    target.style.display = 'none';
  }
  
  return false;
}

function sendMessage() {
  var titre = document.getElementById('titre').value;
  var mail = document.getElementById('mail').value;
  var message = document.getElementById('message').value;
  var captcha = document.getElementById('captcha').value;
  
  var xhr = null;
  
  if(window.XMLHttpRequest || window.ActiveXObject) {
    if(window.ActiveXObject) {
      try {
        xhr = new ActiveXObject('Msxml2.XMLHTTP');
      } catch(e) {
        xhr = new ActiveXObject('Microsoft.XMLHTTP');
      }
    } else {
      xhr = new XMLHttpRequest();
    }
  } else {
    return true;
  }
  
  if(xhr && xhr.readyState != 0) {
    xhr.abort();
    return true;
  }
  
  xhr.onreadystatechange = function(){
    if(xhr.readyState == 2 || xhr.readyState == 3) {
      document.getElementById('submitButton').value = '';
      document.getElementById('submitButton').style.backgroundImage = "url('templates/images/load.gif')";
    } else if(xhr.readyState == 4 && (xhr.status == 200 || xhr.status == 0)) {
      document.getElementById('submitButton').value = 'Envoyer';
      document.getElementById('submitButton').style.backgroundImage = '';
      alert(xhr.responseText);
    }
  };
  
  xhr.open('POST', 'contact.php');
  xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
  xhr.send('titre='+ titre +'&mail='+ mail +'&message='+ message +'&captcha='+ captcha);
  
  return false;
}