javascript操作cookie的方法

1.servlet或者jsp设置的cookie是可以用javascript来读取的,但是设置就会出现重名的现象.


2.24小时弹出一个消息框,告诉用户分享资源,这样的功能用cookie是再合适不过了.



1.以下的代码是javascript实现cookie用到的基础方法:

function GetCookieVal(offset)
//获得Cookie解码后的值
{
var endstr = document.cookie.indexOf (";", offset);
if (endstr == -1)
endstr = document.cookie.length;
return unescape(document.cookie.substring(offset, endstr));
}
function SetCookie(name, value)
//设定Cookie值
{
var expdate = new Date();
var argv = SetCookie.arguments;
var argc = SetCookie.arguments.length;
var expires = (argc > 2) ? argv[2] : null;
var path = (argc > 3) ? argv[3] : null;
var domain = (argc > 4) ? argv[4] : null;
var secure = (argc > 5) ? argv[5] : false;
expdate.setTime(expdate.getTime() + 1000*60*60*24 );//设置cookie在客户端的存活时间
document.cookie = name + "=" + escape (value)+"; expires="+ expdate.toGMTString() + ";path=/";//设置根路径和存活的时间
}
function DelCookie(name)
//删除Cookie
{
var exp = new Date();
exp.setTime (exp.getTime() - 1);
var cval = GetCookie (name);
document.cookie = name + "=" + cval + "; expires="+ exp.toGMTString();
}
function GetCookie(name)
//获得Cookie的原始值
{
var arg = name + "=";
var alen = arg.length;
var clen = document.cookie.length;
var i = 0;
while (i < clen)
{
var j = i + alen;
if (document.cookie.substring(i, j) == arg)
return GetCookieVal (j);
i = document.cookie.indexOf(" ", i) + 1;
if (i == 0) break;
}
return null;
}
//公共处理发表feed
function getFeedStatus(num){
var cookieName = "FEED_COOKIE_STATE";
var result = false;
if( cookieName==null || cookieName=="" ){
return result;
}
var cookieValue = GetCookie(cookieName);
if(cookieValue==null){
return result;
}
if( num>=cookieValue.length || num<0 ){
return result;
}
if(cookieValue.charAt(num)!=null && cookieValue.charAt(num)=="0"){
cookieValue = cookieValue.substring(0,num) + "1" + cookieValue.substring(num+1);
SetCookie(cookieName,cookieValue);
result = true;
}
return result;
}