function valider(input)
     {
	if (input == "") return true;

	var bad = "#$%&*~|[]{}+=_";	
	var okay = true;

	for (i=0;i<=input.length;i++)
	   {
		var c = input.substr(i,1);
		if (c!="" && bad.indexOf(c) > -1)
		 {
			okay = false;
		 }
	   }

	return okay;
     }