js读取浏览器cookie

// 设置Cookie
document.cookie = "username=John Doe; expires=Thu, 18 Dec 2023 12:00:00 UTC; path=/";

// 读取Cookie
var cookies = document.cookie.split(';');
for (var i = 0; i < cookies.length; i++) {
    var cookie = cookies[i].trim();
    if (cookie.indexOf("username=") == 0) {
        var username = cookie.substring("username=".length, cookie.length);
        console.log("Username is: " + username);
    }
}

// 设置Cookie时进行编码
function setCookie(name, value, days) {
    var expires = "";
    if (days) {
        var date = new Date();
        date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
        expires = "; expires=" + date.toUTCString();
    }
    document.cookie = name + "=" + encodeURIComponent(value) + expires + "; path=/";
}

// 读取Cookie时进行解码
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 decodeURIComponent(c.substring(nameEQ.length, c.length));
    }
    return null;
}

// 使用示例
setCookie("username", "John Doe", 7);
console.log(getCookie("username")); // 输出: John Doe