title: How to show alert for duplicated value of textbox
body: <p>I have multiple <code>input</code> fields with different values. I can edit them but cannot be empty (if empty show an alert). When I am editing it to new values, if the new value matches with any of the other inputs values, I need an alert <em>that you cannot use this</em>.</p>
  
  <p><strong>HTML</strong></p>
  
  <pre><code>&lt;input type="text" class="selector" value="new"&gt;
  &lt;input type="text" class="selector" value="old"&gt;
  &lt;input type="text" class="selector" value="newest"&gt;
  &lt;input type="text" class="selector" value="oldest"&gt;
  &lt;input type="text" class="selector" value="older"&gt;
  </code></pre>
  
  <p><strong>JavaScript</strong></p>
  
  <pre><code>$('.selector').change(function () {
      alert();
  });
  </code></pre>
  
  <p>Fiddle <a href="http://jsfiddle.net/iamraviteja/0c0qep6y/" rel="nofollow">here</a></p>