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javascript cookie

2024-11-12 04:22:01   204人阅读

jquery.cookie.js 是一款轻量级的 cookie 插件，能够读取，写入和删除 cookie。

本文主要针对 jquery.cookie.js 的使用方法进行具体的介绍。

用法：

设置 cookie：

$.cookie(‘the_cookie‘, ‘the_value‘);

注：假设 $.cookie 没有第三个參数。那么当浏览器关闭时，该 cookie 将会自己主动删除。

设置一个有效期为 7 天的 cookie：

$.cookie(‘the_cookie‘, ‘the_value‘, {expires: 7});

注：$.cookie 第三个參数是一个对象，除了能够设置有效期（expires: 7）。还能够设置有效路径（path: ‘/‘）、有效域（domain: ‘jquery.com‘）及安全性（secure: true）。

读取 cookie：

$.cookie(‘the_cookie‘);

注：假设没有该 cookie，返回 null。

删除 cookie：

$.cookie(‘the_cookie‘, null);

我们仅仅须要给须要删除的 cookie 设置为 null。就能够删除该 cookie。

最后附上源码：

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/**
 * Cookie plugin
 *
 * Copyright (c) 2006 Klaus Hartl (stilbuero.de)
 * Dual licensed under the MIT and GPL licenses:
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 *
 */

/**
 * Create a cookie with the given name and value and other optional parameters.
 *
 * @example $.cookie(‘the_cookie‘, ‘the_value‘);
 * @desc Set the value of a cookie.
 * @example $.cookie(‘the_cookie‘, ‘the_value‘, { expires: 7, path: ‘/‘, domain: ‘jquery.com‘, secure: true });
 * @desc Create a cookie with all available options.
 * @example $.cookie(‘the_cookie‘, ‘the_value‘);
 * @desc Create a session cookie.
 * @example $.cookie(‘the_cookie‘, null);
 * @desc Delete a cookie by passing null as value. Keep in mind that you have to use the same path and domain
 *       used when the cookie was set.
 *
 * @param String name The name of the cookie.
 * @param String value The value of the cookie.
 * @param Object options An object literal containing key/value pairs to provide optional cookie attributes.
 * @option Number|Date expires Either an integer specifying the expiration date from now on in days or a Date object.
 *                             If a negative value is specified (e.g. a date in the past), the cookie will be deleted.
 *                             If set to null or omitted, the cookie will be a session cookie and will not be retained
 *                             when the the browser exits.
 * @option String path The value of the path atribute of the cookie (default: path of page that created the cookie).
 * @option String domain The value of the domain attribute of the cookie (default: domain of page that created the cookie).
 * @option Boolean secure If true, the secure attribute of the cookie will be set and the cookie transmission will
 *                        require a secure protocol (like HTTPS).
 * @type undefined
 *
 * @name $.cookie
 * @cat Plugins/Cookie
 * @author Klaus Hartl/klaus.hartl@stilbuero.de
 */

/**
 * Get the value of a cookie with the given name.
 *
 * @example $.cookie(‘the_cookie‘);
 * @desc Get the value of a cookie.
 *
 * @param String name The name of the cookie.
 * @return The value of the cookie.
 * @type String
 *
 * @name $.cookie
 * @cat Plugins/Cookie
 * @author Klaus Hartl/klaus.hartl@stilbuero.de
 */
jQuery.cookie = function(name, value, options) {
    if (typeof value != ‘undefined‘) { // name and value given, set cookie
        options = options || {};
        if (value =http://www.mamicode.com/== null) {
            value = ‘‘;
            options = $.extend({}, options); // clone object since it‘s unexpected behavior if the expired property were changed
            options.expires = -1;
        }
        var expires = ‘‘;
        if (options.expires && (typeof options.expires == ‘number‘ || options.expires.toUTCString)) {
            var date;
            if (typeof options.expires == ‘number‘) {
                date = new Date();
                date.setTime(date.getTime() + (options.expires * 24 * 60 * 60 * 1000));
            } else {
                date = options.expires;
            }
            expires = ‘; expires=‘ + date.toUTCString(); // use expires attribute, max-age is not supported by IE
        }
        // NOTE Needed to parenthesize options.path and options.domain
        // in the following expressions, otherwise they evaluate to undefined
        // in the packed version for some reason...
        var path = options.path ? ‘; path=‘ + (options.path) : ‘‘;
        var domain = options.domain ?
 ‘; domain=‘ + (options.domain) : ‘‘;
        var secure = options.secure ? ‘; secure‘ : ‘‘;
        document.cookie = [name, ‘=‘, encodeURIComponent(value), expires, path, domain, secure].join(‘‘);
    } else { // only name given, get cookie
        var cookieValue = http://www.mamicode.com/null;
        if (document.cookie && document.cookie != ‘‘) {
            var cookies = document.cookie.split(‘;‘);
            for (var i = 0; i < cookies.length; i++) {
                var cookie = jQuery.trim(cookies[i]);
                // Does this cookie string begin with the name we want?
                if (cookie.substring(0, name.length + 1) == (name + ‘=‘)) {
                    cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
                    break;
                }
            }
        }
        return cookieValue;
    }
};
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cookie 的应用——记住username

以下我们通过一个实例来应用cookie.js。

最常见的就是记住username，当用户登录过一次后，通过 cookie 记录下该用户的账号和password，这样下次打开页面的时候不用再次输入账号password了。附上代码：

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<!DOCTYPE HTML>
<html lang="en-US">
<head>
    <meta charset="UTF-8">
    <title>cookie的应用——记住用户名</title>
</head>
<body>
    <form action="#" id="myform">
        <label for="username">用户名：</label><input type="text" name="username" id="username" />
        <label for="userpass">密码：</label><input type="password" name="userpass" id="userpass" />
        <input type="submit" value="登录" />
        <a href="javascript:;">清除记录</a>
    </form>
</body>
</html>
<script type="text/javascript" src="cookie.js"></script>
<script type="text/javascript">
window.onload = function(){
    var oForm = document.getElementById(‘myform‘);
    var oTxt1 = document.getElementById(‘username‘);
    var oTxt2 = document.getElementById(‘userpass‘);
    var oClear = document.getElementsByTagName(‘a‘)[0];
    oTxt1.value = getCookie(‘username‘);
    oTxt2.value = getCookie(‘userpass‘);
    
    oForm.onsubmit = function(){
        setCookie(‘username‘,oTxt1.value,30);
        setCookie(‘userpass‘,oTxt2.value,30);
    }
    oClear.onclick = function(){
        removeCookie(‘username‘);
        removeCookie(‘userpass‘);
        oTxt1.value = ‘‘;
        oTxt2.value = ‘‘;
    }
}
</script>
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