function on_before_login (form) {
	//form.login.value = encode64(form.login.value);
	var fields = [   "login"
					, "password"
				];
	
	for (var i=0; i<fields.length; i++) {
		var cmd = "(form." + fields[i] + ".value == '')";
		if (eval(cmd)) {
			alert("Campo obrigat\u00f3rio n\u00e3o preenchido!");
			cmd = "form." + fields[i] + ".focus()";
			eval(cmd);
			return false;
		}
	}

	encodePass(form.password, form.senha);
	clearPass(form);
	return true;
}