如何在Smarty模板中使用`$ _SERVER ['DOCUMENT_ROOT']？

How can I use the $_SERVER['DOCUMENT_ROOT'] in my Smarty template?

// there can not shows the `$_SERVER['DOCUMENT_ROOT']`
{else}
    <h1>{$_SERVER['DOCUMENT_ROOT']}</h1>
    {*{include file=$_SERVER['DOCUMENT_ROOT']|cat:'/templates/NeWorld/qicloud_ext/qicloud_products/clientareaproducts_ext/templates/qicloud_dedicate_server.tpl'}*}  // there also do not work
{/if}


// but there works fine, it can import the script
<script type="text/JavaScript" src='{$_SERVER['DOCUMENT_ROOT']}/templates/NeWorld/qicloud_ext/qicloud_products/clientareaproducts_ext/js/clientareaproducts.js'>
</script>