String.prototype.warn = function(st) {
 var text = this;
 var imgs = Array(
  'info',
  'ok',
  'erreur'
 );
 img = imgs[st];
 var u = document.getElementById(typeof(warnId) != 'undefined' ? warnId : 'warninginfo');
 if (typeof(imagePath) == 'undefined') imagePath = 'img/';
 u.innerHTML = '<img src="'+imagePath+img+'.gif" alt="'+img+'" /> '+text;
 u.onclick = function() {
  u.style.display = 'none';
 }
 u.style.display = 'block';
 return true;
}