title: Determining if all attributes on a javascript object are null or an empty string
body: <p>What is the most elegant way to determine if all attributes in a javascript object are either null or the empty string?  It should work for an arbitrary number of attributes.</p>
  
  <pre><code>{'a':null, 'b':''} //should return true for this object
  {'a':1, 'b':''} //should return false for this object
  {'a':0, 'b':1} //should return false
  {'a':'', 'b':''} //should return true
  </code></pre>