Закругление углов с помощью jq

<script src="http://ms-studio.do.am/file/JS/blok.js" language="javascript"></script>  
<script src="http://ms-studio.do.am/file/JS/1.js" language="javascript"></script>

body{padding: 0px 0 0;background:#FFF;  
  font: 100.01%/1.3 Verdana,Arial,}  
div#box{width: 30em;padding: 15px;margin:0 auto;  
  background:#E6E6E6;color:#000}  
h1{font: lighter 200% "Trebuchet MS",Arial sans-serif;color: #208BE1}  
h1,p{margin:0;padding:10px 20px}  
/*Nifty Corners Cube CSS by Alessandro Fulciniti  
The following classes are added dinamically by javascript,  
and their use should be avoided in the markup */  

b.niftycorners,b.niftyfill{display:block}  
b.niftycorners *{display:block;height: 1px;line-height:1px;font-size: 1px;  
  overflow:hidden;border-style:solid;border-width: 0 1px}  
/*normal*/  
b.r1{margin: 0 3px;border-width: 0 2px}  
b.r2{margin: 0 2px}  
b.r3{margin: 0 1px}  
b.r4{height: 2px}  
b.rb1{margin: 0 8px;border-width:0 2px}  
b.rb2{margin: 0 6px;border-width:0 2px}  
b.rb3{margin: 0 5px}  
b.rb4{margin: 0 4px}  
b.rb5{margin: 0 3px}  
b.rb6{margin: 0 2px}  
b.rb7{margin: 0 1px;height:2px}  
b.rb8{margin: 0;height:2px}  
b.rs1{margin: 0 1px}  
/*transparent inside*/  
b.t1{border-width: 0 5px}  
b.t2{border-width: 0 3px}  
b.t3{border-width: 0 2px}  
b.t4{height: 2px}  
b.tb1{border-width: 0 10px}  
b.tb2{border-width: 0 8px}  
b.tb3{border-width: 0 6px}  
b.tb4{border-width: 0 5px}  
b.tb5{border-width: 0 4px}  
b.tb6{border-width: 0 3px}  
b.tb7{border-width: 0 2px;height:2px}  
b.tb8{border-width: 0 1px;height:2px}  
b.ts1{border-width: 0 2px}

<div id="box">  
<h1>Заголовок</h1>  

Текст</p>  
</div>