js中设置Cookie

//取得cookie
function GetCookie(name) {
    var arg = name + "=";
    var alen = arg.length;
    var clen = window.document.cookie.length;
    var i = 0;
    while (i < clen) {
        var j = i + alen;
        if (window.document.cookie.substring(i, j) == arg) 
           return getCookieVal (j);
        i = window.document.cookie.indexOf(" ", i) + 1;
        if (i == 0) 
          break;
   }
   return null;
}
//取出cookie的值
function getCookieVal (offset) {
    var endstr = window.document.cookie.indexOf (";", offset);
    if (endstr == -1) 
         endstr = window.document.cookie.length;
    return unescape(window.document.cookie.substring(offset, endstr));
}

//设置cookie
function SetCookie (name, value) {

    var exp = new Date();
    exp.setTime(exp.getTime() + (30*24*60*60*1000));
    window.document.cookie = name + "=" + escape (value)+ ";          expires=" + exp.toGMTString()+";path=/";
}
function DeleteCookie (name) {
    var exp = new Date();
    exp.setTime (exp.getTime() - 1);
    var cval = GetCookie (name);
    window.document.cookie = name + "=" + cval + "; expires=" +    exp.toGMTString()+";path=/";
}