How to check 'undefined' value in jquery
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/27509/detecting-an-undefined-object-property-in-javascript">Detecting an undefined object property in JavaScript</a><br>
  <a href="http://stackoverflow.com/questions/2778901/javascript-undefined-compare">javascript undefined compare</a>  </p>
</blockquote>



<p>How we can put a check for undefined like:</p>

<pre><code>function A(val){
  if(val == undefined) 
    //do this
  else
   //do this
}
</code></pre>
