title: Remove certain elements from map in Javascript
body: <p>how can i remove all the key/value pairs from following map, where <strong>key starts with X</strong>.  </p>
  
  <pre><code>var map = new Object(); 
  map[XKey1] = "Value1";
  map[XKey2] = "Value2";
  map[YKey3] = "Value3";
  map[YKey4] = "Value4";
  </code></pre>
  
  <p><strong>EDIT</strong></p>
  
  <p>Is there any way through regular expression, probably using ^ .
  Something like map[^XKe], where <strong>key starts with 'Xke' instead of 'X'</strong></p>