title: make a value selected in drop down when editing
body: <p>I am adding a feature to edit the ads a user puts. For that I want to make the value selected which is selected by the user when he entered the values . How can I implement this?</p>
  
  <pre><code>&lt;div class="nm"&gt;
    Category
  &lt;/div&gt;
  &lt;div class="fl"&gt;
    &lt;select name="category" id = "ad_category" onchange="cangeSubCat(this.value)" &gt;
      &lt;option value=""&gt;---Select Category---&lt;/option&gt;
      &lt;option value="real_estate"&gt;Real Estate&lt;/option&gt;
      &lt;option value="hotels_resturants"&gt;Hotels and Resturants&lt;/option&gt;
      &lt;option value="car"&gt;Car Rental&lt;/option&gt; 
    &lt;/select&gt;
  &lt;/div&gt;
  </code></pre>