'save as' box with Javascript/PHP

Question

On my website I have a JavaScript function that using PHP function creates a file locally on my server (same directory as the website files). The name of this file is known only to these JavaScript and PHP functions. I want to open a regular 'Save As' box to the user to download this file. Is there a way to do this using Javascript/PHP in a manner that will work for Firefox, Chrome and Explorer/Edge? (Only the Javascript/PHP know the file name)

This is the PHP example:

file_put_contents($filename,$txt);
header('content-type: application/text');
header('content-disposition: attachment; filename=' . $filename);
readfile($filename);

Answer 1

In chrome & firefox it saves automatically and in IE a window opens so if a user has not changed their settings by default will they see the where to save dialog regardless of the browser they're using. go to

https://support.google.com/chrome/answer/95574?hl=en-GB

For more information. You can use php code for downloading the file from your server.

header('content-type: application/[type]');
header('content-disposition: attachment; filename=yourfile.file-extension');
readfile('yourfile.file-extension');

for a large file, you can use

function readfileChunked($filename, $retbytes=true){
 $chunksize = 1*(1024*1024);
 $buffer = '';
 $cnt = 0;
 $handle = fopen($filename, 'rb');
 if ($handle === false) {
 return false;
 }
 while (!feof($handle)) {
 $buffer = fread($handle, $chunksize);
 echo $buffer;
 ob_flush();
 flush();
 if ($retbytes) {
 $cnt += strlen($buffer);
 }
 }
 $status = fclose($handle);
 if ($retbytes && $status) {
 return $cnt; // return num. bytes delivered like readfile() does.
 }
 return $status;
 }
header('Pragma: public'); // required
header('Expires: 0'); // no cache
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Cache-Control: private',false);
header('Content-Type: application/force-download');
header('Content-Disposition: attachment; filename="'.$name.'"');
header('Content-Transfer-Encoding: binary');
header('Content-Length: '. get_remote_size($url) );
header('Connection: close');
readfileChunked( $url );

• John Ellis: Using this code, the file (.txt) content is displayed in the webpage itself instead of being downloaded as a file...
• Kumar: @JohnEllis See the answer I have changed.