function html_validar(e) 
{ 
  var html_checkOK = "0123456789ABCDEFGHIJKLMNÑOPQRSTUVWXYZÁÉÍÓÚ" + "abcdefghijklmnñopqrstuvwxyzáéíóú "+".,@#-~*$&%'?¿!¡(){}:;+"+"_";
  html_tecla = (document.all) ? e.keyCode : e.which; 

  if (html_tecla==8 || html_tecla==9) return true; 

  var html_checkStr = String.fromCharCode(html_tecla);

  var html_allValid = true; 
  for (i = 0; i < html_checkStr.length; i++) {
    ch = html_checkStr.charAt(i); 
    for (j = 0; j < html_checkOK.length; j++)
      if (ch == html_checkOK.charAt(j))
        break;
    if (j == html_checkOK.length) { 
      html_allValid = false; 
      break; 
    }
  }
  return html_allValid;
}