【JavaScript代码实现四】获取和设置 cookie

// 创建cookie
function setCookie(name, value, expires, path, domain, secure) {
    var cookieText = encodeURIComponent(name) + '=' +encodeURIComponent(value);
    if (expires instanceof Date) {
        cookieText += '; expires=' + expires;        
    }
    if (path) {
        cookieText += '; expires=' + expires;        
    }
    if (domain) {
        cookieText += '; domain=' + domain;        
    }
    if (secure) {
        cookieText += '; secure';                
    }
    document.cookie = cookieText;
}
// 获取cookie
function getCookie(name) {
    var cookieName = encodeURIComponent(name) + '=';
    var cookieStart = document.cookie.indexOf(cookieName);
    var cookieValue = null;
    if (cookieStart > -1) {
        var cookieEnd = document.cookie.indexOf(';', cookieStart);
        if (cookieEnd == -1) {
            cookieEnd = document.cookie.length;
        }
        cookieValue = decodeURIComponent(document.cookie.substring(cookieStart + cookieName.length, cookieEnd));
    }
    return cookieValue;
}
// 删除cookie
function unsetCookie(name) {
    document.cookie = name + "= ; expires=" + new Date(0);  
}