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<html>
<head>
<script type="text/javascript">
var timer
i=0
j=0
k=0
l=160
m=120

function setlight()
{
document.getElementById('light_div').filters[0].clear()

if (i<100)
	{
	document.getElementById('light_div').filters[0].addcone(0,0,0,50,50,100,120,200,i,100)
	}
else
	{
	if (j<160)
		{
		document.getElementById('light_div').filters[0].addcone(j,0,0,50,50,100,120,200,i,200)
		j++
		}
	else
		{
		if (k<120)
			{
			document.getElementById('light_div').filters[0].addcone(j,k,0,50,50,100,120,200,i,200)
			k++
			}
		else
			{
			if (l>0)
				{
				l--
				document.getElementById('light_div').filters[0].addcone(l,k,0,50,50,100,120,200,i,200)
				}
			else
				{
				if (m>0)
					{
					m--
					document.getElementById('light_div').filters[0].addcone(l,m,0,50,50,100,120,200,i,200)
					}
				else
					{
					stoptimer()
					}
				}				
			}			
		}
	}
i++
timer=setTimeout("setlight()",1)
}

function stoptimer()
{
clearTimeout(timer)
}
</script>
<style>
div
{
width:100px;
}
body
{
background:#000000;
}
</style>
</head>

</html>

W3School TIY Editor