Viewing PHP File Output as XML in Firefox (and other browsers) [duplicate]

This question already has answers here: Output raw XML using php (5 answers) Closed 3 years ago.

I have a PHP file which echoes an XML output. However, whenever I go to view that PHP file through Firefox (I haven't tried IE or Chrome), I get a raw text output like seen in this image:

http://numberonekits.com/Screenshot.png

It seems to me that, since the file is a PHP file, Firefox interprets it as such and does not try to display it as an XML tree, despite its XML heading. I am aw开发者_运维问答are that one solution would be to send the output to a separate file with a .xml extension, but I know there must be an easier way. I guess what I am really trying to find out is how to get Firefox to recognize the XML format and display it as it should. Any help is greatly appreciated.

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Tell the browser you are sending it an XML file:

header('Content-Type: text/xml');