js设置、修改、获取、删除 cookie

function setCookie(name,value){
    var Days = 30;
    var exp = new Date();
    exp.setTime(exp.getTime() + Days*24*60*60*1000);
    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}

/**
 * 设置cookie
 * @param {string} name  键名
 * @param {string} value 键值
 * @param {integer} days cookie周期
 */
function setCookie(name,value,days) {
    if (days) {
        var date = new Date();
        date.setTime(date.getTime()+(days*24*60*60*1000));
        var expires = "; expires="+date.toGMTString();
    }else{
        var expires = "";
    }
    document.cookie = name+"="+value+expires+"; path=/";
}
// 获取cookie
function getCookie(name) {
    var nameEQ = name + "=";
    var ca = document.cookie.split(';');
    for(var i=0;i < ca.length;i++) {
        var c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1,c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
    }
    return null;
}
// 删除cookie
function deleteCookie(name) {
    setCookie(name,"",-1);
}