设置cookie
document.cookie=”name=”+username;
function setCookie(name,value)
{
var Days = 30;
var exp = new Date();
exp.setTime(exp.getTime() + Days*24*60*60*1000);
document.cookie = name + “=”+ escape (value) + “;expires=” + exp.toGMTString();
}

读取cookies
function getCookie(name)
{
var arr,reg=new RegExp(“(^| )”+name+”=([^;]*)(;|$)”);
if(arr=document.cookie.match(reg))
return unescape(arr[2]);
else
return null;
}

删除cookies
function delCookie(name)
{
var exp = new Date();
exp.setTime(exp.getTime() – 1);
var cval=getCookie(name);
if(cval!=null)
document.cookie= name + “=”+cval+”;expires=”+exp.toGMTString();
}