title: AS3 XML object not throwing exception if invalid data is given?
body: <p>I remember darkly that the XML class in AS3 would throw an exception if you tried to give it data in it's constructor that was not a valid XML string. But now I got a case where the XML happily takes every kind of data no matter it's valid XML or not...</p>
  
  <pre><code>var xml:XML;
  try
  {
      xml = new XML("Some bogus string content.");
      _valid = true;
  }
  catch (err:Error)
  {
      _valid = false;
  }
  </code></pre>
  
  <p>... am I missing something??</p>
  
  <p>Update:
  Qname somehow is null but somehow it's not, see here:</p>
  
  <pre><code>var qname:QName = xml.name();
  if (!qname.localName)
  {
      _valid = false;
  }
  </code></pre>
  
  <p>... throws an exception. Obvioulsy qname is null! But ...</p>
  
  <pre><code>var qname:QName = xml.name();
  if (!qname || !qname.localName)
  {
      _valid = false;
  }
  </code></pre>
  
  <p>... doesn't throw any exception. qname seems not to be null. WTH?</p>