title: isset in jQuery?
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/7227087/finding-whether-the-element-exists-in-whole-html-page">Finding whether the element exists in whole html page</a>  </p>
  </blockquote>
  
  
  
  <p>i would like make somethings:</p>
  
  <p><strong>HTML</strong>:</p>
  
  <pre><code>&lt;span id="one"&gt;one&lt;/span&gt;
  &lt;span id="two"&gt;two&lt;/span&gt;
  &lt;span id="three"&gt;three&lt;/span&gt;
  </code></pre>
  
  <p><strong>JavaScript</strong>:</p>
  
  <pre><code>if (isset($("#one"))){
     alert('yes');
  }
  
  if (isset($("#two"))){
     alert('yes');
  }
  
  if (isset($("#three"))){
     alert('yes');
  }
  
  if (!isset($("#four"))){
     alert('no');
  }
  </code></pre>
  
  <p>LIVE:</p>
  
  <p><a href="http://jsfiddle.net/8KYxe/" rel="noreferrer">http://jsfiddle.net/8KYxe/</a></p>
  
  <p>how can I make that?</p>