检查cookie是否存在cookie

Question

检查cookie是否存在的好方法是什么？

条件：

Cookie存在，如果

cookie1=;cookie1=345534;
//or
cookie1=345534;cookie1=;
//or
cookie1=345534;

如果不存在Cookie，

cookie=;
//or
<blank>

Answer 1

您可以使用所需cookie的名称调用函数getCookie，然后检查其是否为null。

function getCookie(name) {
    var dc = document.cookie;
    var prefix = name + "=";
    var begin = dc.indexOf("; " + prefix);
    if (begin == -1) {
        begin = dc.indexOf(prefix);
        if (begin != 0) return null;
    }
    else
    {
        begin += 2;
        var end = document.cookie.indexOf(";", begin);
        if (end == -1) {
        end = dc.length;
        }
    }
    // because unescape has been deprecated, replaced with decodeURI
    //return unescape(dc.substring(begin + prefix.length, end));
    return decodeURI(dc.substring(begin + prefix.length, end));
}

function doSomething() {
    var myCookie = getCookie("MyCookie");

    if (myCookie == null) {
        // do cookie doesn't exist stuff;
    }
    else {
        // do cookie exists stuff
    }
}