代码如下：

function getCookie(key){        var cookies=document.cookie;        if(cookies.length>0){            var start=cookies.indexOf(key+"=");            if(start<0){                return "";            }            var end =cookies.indexOf(";",start);            if(end<0){                end=cookies.length;            }            return cookies.substring(start+key.length+1,end);        }    }

或者

function getCookie(cookieName) {    var strCookie = document.cookie;    var arrCookie = strCookie.split("; ");    for(var i = 0; i < arrCookie.length; i++){        var arr = arrCookie[i].split("=");        if(cookieName == arr[0]){            return arr[1];        }    }    return "";}

简单来说浏览器的cookie是通过document.cookie存放的格式类似于，"t=2;r=3;t=4"的形式，按照这个形式进行截取就好了