这个小小的js怎么不能成功?

Question

这个是延时的 ，要想持续执行要使用 setInetval

Answer 1

详细点么?
setInetval怎么用?

Answer 2

<div id='id'>2</div>
<script type="text/javascript">
function refreshFrame()
{
document.getElementById('id').innerHTML += '1';
}
window.setInterval(refreshFrame,1000);
</script>

Answer 3

<div   id='id'>2</div> 
<script   type="text/javascript"> 
function refreshFrame() 
{
var val=document.getElementById('id').innerHTML;
val=val/1+1;
document.getElementById('id').innerHTML=val; 
} 
window.setInterval(refreshFrame,1000);
</script>