This might be one way 
use CGI;
if( CGI->http('accept') =~ m'\Qapplication/xhtml+xml\E'i ){
   print CGI->header( 'application/xhtml+xml; charset=utf-8 ');
} else {
   print CGI->header( 'text/html; charset=utf-8 ');
}

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CGI, CGI Programming

In reply to Re: well formed XHTML != tag soup by Anonymous Monk
in thread well formed XHTML != tag soup by CamelDung

Title:
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