use strict;
use warnings;
my @strings = (
    "http://mysite/bbsui.jsp?id=dxpwd",
    "http://mysite/bbsui.jsp?id=dxpsf",
    "http://mysite/bbsui.jsp?id=sfpwd",
    "http://mysite/bbsui.jsp?id=ds35e",
    "http://mysite/bbsui.jsp?id=124536"
);

for ( @strings ) {
    my ($id) = split( /=/, $_)[1];
    print "Id: $id\n";
}

##</code><code>##

$xyz = "http://mysite/bbsui.jsp?id=dxpwd";
$id = $1 if ($xyz =~ m/\?id=(.+?)$/i);