#!/usr/bin/perl
use HTML::TreeBuilder;
use URI;

#Specify valid hosts and domains here. The script will skip these. 
my @domains = ( "example.com",
				"img.example.com",
				"js.example.com" );

#Parse each file passed via the command line:
foreach my $file_name (@ARGV) {
    my $tree     = HTML::TreeBuilder->new;    
    $tree->parse_file($file_name);		
    $tree->elementify();					  
    @elements = $tree->find("script");		#Find each instance of the "script" tag
    foreach my $element (@elements) {		  
        my $src  = $element->attr("src");   #Get the results of the SRC attribute
		if( $src ) {						  
        	$url  = URI->new($src);				
        	$host = $url->host;
			if(!(grep( /$host/i, @domains ))) {
	        	print $host;				#Print just the SRC URL's Host
			}
		}
    }
    $tree = $tree->delete;					  #Delete the tree to start over for the next file
}