请教

<script>
function getCookieVal(offset)
{
var iEndStr=document.cookie.indexOf(";",offset);
if(iEndStr==-1)
iEndStr=document.cookie.length;
return unescape(document.cookie.substring(offset,iEndStr));
}
function getCookie(name)
{
var strArg=name+"=";
var iArgLength=strArg.length;
var iCookieLength=document.cookie.length;
var iIndex=0;
while(iIndex<iCookieLength)
{
var kIndex=iIndex+iArgLength;
if(document.cookie.substring(iIndex,kIndex)==strArg)
return getCookieVal(kIndex);
iIndex=document.cookie.indexOf(" ",iIndex)+1;
if(iIndex==0)
break;
}
return null;
}
function setCookie(name,value)
{
var strArgValue=setCookie.arguments;
var iArgLength=setCookie.arguments.length;
var expires=(2<iArgLength)?strArgValue[2]:null;
var path=(3<iArgLength)?strArgValue[3]:null;
var domain=(4<iArgLength)?strArgValue[4]:null;
var secure=(5<iArgLength)?strArgValue[5]:false;
document.cookie=name+"="+escape(value)+((expires==null)?"":(";expires="+expires.toGMTString()))+
((path==null)?"":(";path="+path))+((domain==null)?"":(";domain="+domain))+
((secure==true)?";secure":"");
}
function setTimer()
{
setInterval("countCount()",60000);
}
var iCountOld=getCookie(document.all.cookieName.value);
var iCountNew=iCountOld;
function countCount()
{
if(iCountNew==0)
{
window.location="about:blank";
}
else
{
iCountNew--;
}
}
</script>
<input text value="Cookie名" disabled style="border:0px solid"><input type=text id="cookieName" style="border:1px solid"><br>
<input text value="Cookie值" disabled style="border:0px solid"><input type=text id="cookieValue" style="border:1px solid"><br>
<br>
<input type=button value="设置Cookie" onclick="setCookie(document.all.cookieName.value,document.all.cookieValue.value)">
<input type=button value="取值Cookie" onclick="window.confirm(getCookie(document.all.cookieName.value))">
<br>
<br>
<input type=button value="启动定时器" onclick="setTimer()">