Response Chinese file name garbled problem solution under FireFox/IE

if (().IndexOf("msie") > -1)
{
downloadfilename = (downloadfilename);
}
if (().IndexOf("firefox") > -1)
{
("Content-Disposition", "attachment;filename=\"" + downloadfilename + "\"");
}
else
{
("Content-Disposition", "attachment;filename=" + downloadfilename);
}