随机改变显示图片，将下列代码加入BODY之间的适当位置
<script language="JavaScript">
<!--

a = 4 // a=numbers of banners
var slump = Math.random();
var talet = Math.round(slump * (a-1))+1;
function create() {

this.width = ''
this.height = ''
this.src = ''
this.href = ''
this.border = ''
this.alt = ''
this.under = ''
}

b = new Array()
for(var i=1; i<=a; i++) { b[i] = new create() }
b[1].src = "blog/template/stariver42/header.jpg"
b[1].href = "#top"
b[1].width = "700"
b[1].height = "200"
b[1].border = "0"
b[1].alt = "欢迎光临竹园下！"

b[2].src = "blog/template/stariver42/header1.jpg"
b[2].href = "#top"
b[2].width = "700"
b[2].height = "200"
b[2].border = "0"
b[2].alt = "Welcome_To_Totti's_Blog!"

b[3].src = "blog/template/stariver42/header2.jpg"
b[3].href = "#top"
b[3].width = "700"
b[3].height = "200"
b[3].border = "0"
b[3].alt = "竹园下－记录着我的生活，收集着我的收集" 

b[4].src = "blog/template/stariver42/header3.jpg"
b[4].href = "#top"
b[4].width = "700"
b[4].height = "200"
b[4].border = "0"
b[4].alt = "竹园下－如风一般的轻盈～" 

var visa = "";

visa += '<a href="'+b[talet].href+'">'
visa += '<img src="'+b[talet].src+'" height='+b[talet].height
visa += ' width='+b[talet].width+' border='+b[talet].border+' alt='+b[talet].alt+'>';
visa += '</a>'
//-->
</SCRIPT><script language="JavaScript">
<!--
document.write('<CENTER>'+visa+'<br>');
document.write(b[talet].under+'</center>');
//--></script>


要点：修改其中每个图形的位置，链接，尺寸，边缘，显示文字和文字超链接。