title: Creating object with dynamic key
body: <p>I have to create a object key based on some dynamic value .
  Here the value of <code>str</code> will from user to user. The user enters the value of str.
  I want to use <code>str</code> value entered by user to create Object.</p>
  
  <pre><code>var str = $('#inputValue');
  
  var obj = new Object();
  obj.assignment = new Object();
  obj.assignment.name= "assignmentName";
  obj.assignment.str = new Object();
  </code></pre>