JavaScript如何创建和读取Cookie中的值？

这是可用于创建和检索cookie的功能。

function createcookie(name, value, days) {    var expires;    if (days) {        var date = new Date();        date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));        expires = "; expires=" + date.toGMTString();    }    else {        expires = "";    }    document.cookie = name + "=" + value + expires + "; path=/";}function getcookie(c_name) {    if (document.cookie.length > 0) {        c_start = document.cookie.indexOf(c_name + "=");        if (c_start != -1) { c_start = c_start + c_name.length + 1; c_end = document.cookie.indexOf(";", c_start); if (c_end == -1) {     c_end = document.cookie.length; } return unescape(document.cookie.substring(c_start, c_end));        }    }    return "";}