SO jQuery Fiddle

Test Fiddle mainly for SO Questions jQuery 1.4.3, UI 1.8.5

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/ui-lightness/jquery-ui.css">
<select id="targetField" multiple="multiple" name="D1" style="width:200px;">
  <option>INDIA</option>
  <option>USA</option>
  <option>UK</option>
  <option>AUSTRALIA</option>
  <option>RUSSIA</option>
  <option>FRANCE</option>
  <option>HOLLAND</option>
</select>

JavaScript

$("select").attr("size", function() { return this.options.length; });