Add optgroup label in dyanamic code by jquery
<p>This is my select box code now</p>

<pre><code>     &lt;select id="header1_cbocity"&gt;  
    &lt;option  value="2"&gt;Ahmedabad&lt;/option&gt;
    &lt;option  value="4"&gt;Bangalore&lt;/option&gt;
    &lt;option  value="14"&gt;Chennai&lt;/option&gt;
    &lt;option  value="20"&gt;Delhi&lt;/option&gt;
    &lt;option  value="33"&gt;Gurgaon&lt;/option&gt;
    &lt;option  value="167"&gt;Switzerland&lt;/option&gt;
    &lt;option  value="261"&gt;Tanzania&lt;/option&gt;
    &lt;option  value="168"&gt;Thailand&lt;/option&gt;
    &lt;option  value="263"&gt;Uganda&lt;/option&gt;
    &lt;option  value="169"&gt;United Kingdom (U.K)&lt;/option&gt;
    &lt;option  value="170"&gt;United States (U.S)&lt;/option&gt;
    &lt;/select&gt;
</code></pre>

<p>and i want to add optgroup label only for country like below     </p>

<pre><code>    &lt;select id="header1_cbocity"&gt;  
        &lt;option  value="2"&gt;Ahmedabad&lt;/option&gt;
        &lt;option  value="4"&gt;Bangalore&lt;/option&gt;
        &lt;option  value="14"&gt;Chennai&lt;/option&gt;
        &lt;option  value="20"&gt;Delhi&lt;/option&gt;
        &lt;option  value="33"&gt;Gurgaon&lt;/option&gt;
    &lt;optgroup label="Country"&gt;
        &lt;option  value="167"&gt;Switzerland&lt;/option&gt;
        &lt;option  value="261"&gt;Tanzania&lt;/option&gt;
        &lt;option  value="168"&gt;Thailand&lt;/option&gt;
        &lt;option  value="263"&gt;Uganda&lt;/option&gt;
        &lt;option  value="169"&gt;United Kingdom (U.K)&lt;/option&gt;
        &lt;option  value="170"&gt;United States (U.S)&lt;/option&gt;
    &lt;/optgroup&gt;
    &lt;/select&gt;
</code></pre>

<p>i am trying with jquery code but couldn't add optgroup label for Country, so i need help</p>
