Cookieを削除するには、空の値を設定して1秒で期限切れになります。詳細には、私は常に次のフレーバーの1つを使用します(私は2番目のフレーバーを好む傾向があります):
1。
    function setCookie(key, value, expireDays, expireHours, expireMinutes, expireSeconds) {
        var expireDate = new Date();
        if (expireDays) {
            expireDate.setDate(expireDate.getDate() + expireDays);
        }
        if (expireHours) {
            expireDate.setHours(expireDate.getHours() + expireHours);
        }
        if (expireMinutes) {
            expireDate.setMinutes(expireDate.getMinutes() + expireMinutes);
        }
        if (expireSeconds) {
            expireDate.setSeconds(expireDate.getSeconds() + expireSeconds);
        }
        document.cookie = key +"="+ escape(value) +
            ";domain="+ window.location.hostname +
            ";path=/"+
            ";expires="+expireDate.toUTCString();
    }
    function deleteCookie(name) {
        setCookie(name, "", null , null , null, 1);
    }
使用法:
setCookie("reminder", "buyCoffee", null, null, 20);
deleteCookie("reminder");
2
    function setCookie(params) {
        var name            = params.name,
            value           = params.value,
            expireDays      = params.days,
            expireHours     = params.hours,
            expireMinutes   = params.minutes,
            expireSeconds   = params.seconds;
        var expireDate = new Date();
        if (expireDays) {
            expireDate.setDate(expireDate.getDate() + expireDays);
        }
        if (expireHours) {
            expireDate.setHours(expireDate.getHours() + expireHours);
        }
        if (expireMinutes) {
            expireDate.setMinutes(expireDate.getMinutes() + expireMinutes);
        }
        if (expireSeconds) {
            expireDate.setSeconds(expireDate.getSeconds() + expireSeconds);
        }
        document.cookie = name +"="+ escape(value) +
            ";domain="+ window.location.hostname +
            ";path=/"+
            ";expires="+expireDate.toUTCString();
    }
    function deleteCookie(name) {
        setCookie({name: name, value: "", seconds: 1});
    }
使用法:
setCookie({name: "reminder", value: "buyCoffee", minutes: 20});
deleteCookie("reminder");
               
              
setCookie('name', 'value', 0)してCookieを削除できます。