Publishing - JavaScript/HTML - Output file extension

[Porcelain]

Is it possible to set not only output filename, but extension too? I have php code in my template, but I can only get html extension in result file

[Preran]

From what I understand, you need a PHP file extension with your output file, is that correct?  I don't think that is possible, but I am glad to be corrected if there is a better answer.