Strange borders around a search box and submit button.

Strange borders around a search box and submit button.

I am using Jquery mobile to create a mobile app. When I create an input box with a submit box I see a strange border-like graphic around it. Please see the attachment



<div class='unit' style='margin-top: -26; margin-left: 0px; width:400px;'>
<form action="restaurant_search.asp" method="get" style="width:100%; ">
<fieldset class="ui-grid-a" style="width:100%; ">
        <div class="ui-block-a" style="width:25%; "><input type="search" name="search-mini" id="search2" data-mini="true" /></div>
   <div class="ui-block-b" style="margin-top: -10px; border-style:hidden;"><button type="submit" name="submit" value="submit-value" data-mini="true" >Submit</button></div>
  </fieldset>
</form>
</div>