クリックすると切り替わる画像

ヘッダ部分
<SCRIPT LANGUAGE="JavaScript">
function changeImg()	{
	var number = Math.floor(Math.random()*10)
	if(number == 0)	{
		document.images[0].src = "0.gif"
	} if(number == 1)	{
		document.images[0].src = "1.gif"
	} if(number == 2)	{
		document.images[0].src = "2.gif"
	} if(number == 3)	{
		document.images[0].src = "3.gif"
	} if(number == 4)	{
		document.images[0].src = "4.gif"
	} if(number == 5)	{
		document.images[0].src = "5.gif"
	} if(number == 6)	{
		document.images[0].src = "6.gif"
	} if(number == 7)	{
		document.images[0].src = "7.gif"
	} if(number == 8)	{
		document.images[0].src = "8.gif"
	} if(number == 9)	{
		document.images[0].src = "9.gif"
	}
}
</SCRIPT>

ボディ部分
<A HREF="javascript:changeImg()"><IMG SRC="0.gif" BORDER=0></A>