If it's throwing an error, then in addition to the if statements, you should perhaps trap the potential errors in an eval block: 
# declare lexical variable *outside the scope of the eval*
my $BusUrl;

# trap potential error
eval {
  $BusUrl = $contact->getElementsByTagName( "BusinessUrl" );
};
# check if tag retrieval failed
if($@) {
  # assign an empty (but defined) string
  $BusUrl = '';
}

$bus_url = $BusUrl->item( 0 )->getChildAtIndex( 0 )->getData();

[download]

__________
The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it.
- Terry Pratchett

In reply to Re: use XML::DOM - what to do with empty tags? by EvanK
in thread use XML::DOM - what to do with empty tags? by kevyt

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.