相关疑难解决方法(0)

我想点击按钮时发送"ajax下载请求",所以我试着这样做:

JavaScript的:

var xhr = new XMLHttpRequest();
xhr.open("GET", "download.php");
xhr.send();

的download.php:

<?
header("Cache-Control: public");
header("Content-Description: File Transfer");
header("Content-Disposition: attachment; filename= file.txt");
header("Content-Transfer-Encoding: binary");    
readfile("file.txt");
?>

但是没有按预期工作,我该怎么办？先感谢您