title: Prevent Multiple Primary When the Checkbox is Checked
body: <p>I have a Form where I want to limit the Data from my Drop Downlist when the checkbox is checked</p>
  
  <p>So when the Is Primary checkbox is Checked , There will be no 2 Email address that the Is Primary is Both True !! That is what i Want to Prevent</p>
  
  <p><img src="https://i.stack.imgur.com/ETHOT.jpg" alt="enter image description here"></p>
  
  <p>So that When i Save theres a Message window that will Appear and Let the user know that he/she checked the checkbox for the Same Drop Down Value</p>
  
  <pre><code>using (Html.BeginForm("Save", "Worker", FormMethod.Post, new { id = "contactForm" }))
  {
      &lt;input type="hidden" id="workerId" name="workerId" value="@workerId" /&gt;
      &lt;p&gt;
          &lt;label for="ddlContactType"&gt;
              Contact Type&lt;/label&gt;
          &lt;span&gt;
               @Html.DropDownList("ddlContactType", new SelectList(ViewBag.ContactTypeList, "ID", "Display_Value", workerContactType), "[Please Select]",
                  new Dictionary&lt;string, object&gt;
                  {
                      {"class","validate[required] inputLong"}
                  })
          &lt;/span&gt;
      &lt;/p&gt;
      &lt;p&gt;
          &lt;label for="txtContactValue"&gt;
              Contact Value&lt;/label&gt;
          &lt;span&gt;
              &lt;input type="text" id="txtContactValue" name="txtContactValue"  class="validate[required] inputLong" value="" /&gt;
              &lt;input type="checkbox" name="chkWorkerIsPrimary" id="chkWorkerIsPrimary" value="true"
                          checked="checked" /&gt;
               &lt;label&gt;
                   Is Primary?&lt;/label&gt;
          &lt;/span&gt;
          &lt;/p&gt; 
          &lt;p&gt;
              &lt;span&gt;
                 &lt;input type="submit" id="btnAdd" class="styledButton" value="Add" /&gt;
              &lt;/span&gt;
          &lt;/p&gt;
      }
  &lt;/div&gt;
  </code></pre>
  
  <p>I need the Validation written in Javascript or Jquery but i dont know how to start :(</p>
  
  <p>Thanks</p>