javascript解析cookie

/*
* WebFXCookie class
*/
function WebFXCookie() {
    if (document.cookie.length) { this.cookies = ' ' + document.cookie; }
}

WebFXCookie.prototype.setCookie = function (key, value) {
    document.cookie = key + "=" + escape(value);
}

WebFXCookie.prototype.getCookie = function (key) {
    if (this.cookies) {
        var start = this.cookies.indexOf(' ' + key + '=');
        if (start == -1) { returnnull; }
        var end = this.cookies.indexOf(";", start);
        if (end == -1) { end = this.cookies.length; }
        end -= start;
        var cookie = this.cookies.substr(start,end);
        return unescape(cookie.substr(cookie.indexOf('=') + 1, cookie.length - cookie.indexOf('=') + 1));
    }
    else { returnnull; }
}



function getCookieVal (offset)
{
    var endstr=document.cookie.indexOf (";",offset);if (endstr==-1)
    endstr=document.cookie.length;return unescape(document.cookie.substring(offset, endstr));
}


function GetCookie (name)
{
    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;
    }
    returnnull;
}
function DeleteCookie (name)
{
    var exp=new Date(); exp.setTime (exp.getTime()-1); var cval=GetCookie (name);
    document.cookie=name+"="+cval+"; expires="+exp.toGMTString();