怎么才能让自动添加停止下来？
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
</head>
</head>
<body>
<ul id="ultt">
<li >勇士</li>
<li >骑士</li>
<li id="litt">雷霆</li>
<li>火箭</li>
</ul>
<script>
function test (){
var aobj= document.createElement("li");
aobj.innerHTML="快船";
ultt.appendChild(aobj )
}
function tian (){
var i =setInterval('test()',1000)
}
</script>
<input type="button" value="自动添加" onclick="tian ()" />
<input type="button" value="停止添加" onclick="clearInterval(i)" />
</body>
</html>
刚毅87