title: Check duplicate value in select before append
body: <p>i want to check duplicate value of select box before append options if first select box value all ready in append list stop new duplicate append.</p>
  
  <p><a href="https://jsfiddle.net/58418x2r/2/" rel="nofollow noreferrer">here is jsFiddle</a></p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>$(function () {
      $("#addtoption").bind("click", function (){
            var div = $("&lt;div /&gt;");
            div.html(GetTransferOpt(""));
            $(".trnlistopt").append(div);
      });
  });
  
  function GetTransferOpt(value) {
      var digit = $('#digit').val();
      var trtyp = $('#type').val();
      var trsdet = $('#number').val();
      return '&lt;span class="dig"&gt;'+digit+'&lt;/span&gt;&amp;nbsp; &amp;nbsp; &amp;nbsp;&lt;span class="trnsto"&gt;'+trtyp+'&lt;/span&gt;&amp;nbsp; &amp;nbsp; &amp;nbsp;&lt;span class="trnsop"&gt;'+trsdet+'&lt;/span&gt;';
  }</code></pre>
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.trnlistopt { padding:20px 0 0}</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"&gt;&lt;/script&gt;
  &lt;p&gt;If first select box value all ready append &lt;/p&gt;
  
  &lt;select name="digit" id="digit"&gt;
    &lt;option&gt;1&lt;/option&gt;
    &lt;option&gt;2&lt;/option&gt;
    &lt;option&gt;3&lt;/option&gt;
    &lt;option&gt;4&lt;/option&gt;
    &lt;option&gt;5&lt;/option&gt;
  &lt;/select&gt;
  
  &lt;select name="type" id="type"&gt;
    &lt;option value="Option 1"&gt;Option 1&lt;/option&gt;
    &lt;option value="Option 2"&gt;Option 2&lt;/option&gt;
    &lt;option value="Option 3"&gt;Option 3&lt;/option&gt;
    &lt;option value="Option 4"&gt;Option 4&lt;/option&gt;
  &lt;/select&gt;
  
  &lt;input type="text" name="number" id="number" value=""&gt;
  
  &lt;input type="button" id="addtoption" value="Add"&gt;
  
  &lt;div class="trnlistopt"&gt;&lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>