title: Alert when selected similar value from multiple check box with the same class name
body: <p>When I select for a second time from the below check box with the same value it should alert '<strong>value is already</strong> checked' How do I do that using jquery?</p>
  
  <pre><code>&lt;div&gt;
      &lt;input type="checkbox" class="check" value="1"/&gt;
  &lt;/div&gt;
  &lt;div&gt;
      &lt;input type="checkbox" class="check" value="2"/&gt;
  &lt;/div&gt;
  &lt;div&gt;
      &lt;input type="checkbox" class="check" value="1"/&gt;
  &lt;/div&gt;
  &lt;div&gt;
      &lt;input type="checkbox" class="check" value="3"/&gt;
  &lt;/div&gt;
  &lt;div&gt;
      &lt;input type="checkbox" class="check" value="4"/&gt;
  &lt;/div&gt;
  &lt;div&gt;
      &lt;input type="checkbox" class="check" value="3"/&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I tried with below code but nothing is working</p>
  
  <pre><code>var itemVal=false;
  $(document).on('change','.check:checked',function(){
      selVal=$(this).val();
      $('.check:checked').each(function(){
          if($(this).val()==selVal)
              itemVal=true;       
      });         
      if(itemVal==true){
          alert('Proceed');
      }else{
          alert('Please choose same name');
      }               
  });
  </code></pre>