print "Content-Disposition: attachment;filename=sample.csv\n";
とやるとOK。
以下サンプル
print "Content-type: text/x-hdml;charset=Shift_JIS\n";
print "Content-Disposition: attachment;filename=sample.csv\n";
print "\n";
for ($i=0; $i<=10; $i++) {
for ($j=0; $j<=10; $j++) {
$_ = ($i * $j);
print "$_,";
}
print "日本語だよ\n";
}ネタ元