function isEmpty(text){
   var enter1 = "\n",
       enter2 = "\r",
       espaco = " ",
       tab = "\t";

   if (text == "") return true;

   //A verifica se o caracter selecionada possui valor vahlido
   for (var indice = 0; indice < text.length; indice++){
      if (text.charAt(indice) != espaco && 
         text.charAt(indice) != tab &&
         text.charAt(indice) != enter1 && 
         text.charAt(indice) != enter2 )
         return false;
   }
   return true;
}