header("Content-type:text/html;charset=utf-8");
$file_name="檔名";	 
$file_path="檔案路徑";
			 
//首先要判斷給定的檔案存在與否
if(!file_exists($file_path)){
    echo "沒有該檔案檔案";
    return ;
}
$fp=fopen($file_path,"r");
$file_size=filesize($file_path);
			 
//下載檔案需要用到的頭
Header("Content-type: application/octet-stream");
Header("Accept-Ranges: bytes");
Header("Accept-Length:".$file_size);
Header("Content-Disposition: attachment; filename=".$file_name);
$buffer=1024;
$file_count=0;
//向瀏覽器返回資料
while(!feof($fp) && $file_count<$file_size){
    $file_con=fread($fp,$buffer);
    $file_count+=$buffer;
    echo $file_con;
}
fclose($fp);