将下拉菜单选择保存在Cookie中？ [英] Saving dropdown menu selection in a cookie?

问题描述

我看过这张贴了几次，但我不能得到的代码工作。
我需要帮助，使此下拉菜单将其设置保存为cookie，所以当用户再次访问网站时，他们以前的选择将保留。

I've seen this posted a few times, but I wasn't able to get the code working at all. I need help making this drop down menu save its settings to a cookie, so when the user visits the site again, their previous selection is retained.

下拉菜单：

<select id="ThemeSelect">
    <option value="zelda">Zelda</option>
    <option value="smb2">SMB 2</option>
</select>

为了参考，这个代码是在Wordpress小部件中使用一些Javascript来改变CSS代码，主题选择器。

For reference, this code is with some Javascript in a Wordpress widget that changes the css code, like a theme selector.

如何将此保存为Cookie？我觉得我已经尝试了一切！

How would I make this save as a cookie? I feel like I've tried everything!

编辑：
我应该说，但我使用这个代码来改变CSS：

I should have said, but I use this code to change the CSS:

var saveclass = null;
var sel = document.getElementById('ThemeSelect');
sel.onchange = function(){
    saveclass = saveclass ? saveclass : document.body.className;
    document.body.className = saveclass + ' ' + sel.value;
};

推荐答案

通过javascript创建Cookie的功能位于
从JavaScript设置Cookie ， javascripter.net。

Something along these lines should work for you. The function to create a cookie via javascript was found in Setting a Cookie from JavaScript, a post on javascripter.net.

HTML ：

<select id="ThemeSelect" onchange="setCookie('theme', this.value, 365);">
    <option value="zelda">Zelda</option>
    <option value="smb2">SMB 2</option>
</select>

Javascript ：

function setCookie(cookieName, cookieValue, nDays) {
    var today = new Date();
    var expire = new Date();

    if (!nDays) 
        nDays=1;

    expire.setTime(today.getTime() + 3600000*24*nDays);
    document.cookie = cookieName+"="+escape(cookieValue) + ";expires="+expire.toGMTString();
}

编辑：

保存Cookie

我已将两个函数合并为一个。

I have merged the two functions into one for you.

HTML ：

<select id="ThemeSelect" onchange="saveTheme(this.value);">
    <option value="zelda">Zelda</option>
    <option value="smb2">SMB 2</option>
</select>

Javascript ：

var saveclass = null;

function saveTheme(cookieValue)
{
    var sel = document.getElementById('ThemeSelect');

    saveclass = saveclass ? saveclass : document.body.className;
    document.body.className = saveclass + ' ' + sel.value;

    setCookie('theme', cookieValue, 365);
}

function setCookie(cookieName, cookieValue, nDays) {
    var today = new Date();
    var expire = new Date();

    if (nDays==null || nDays==0)
        nDays=1;

    expire.setTime(today.getTime() + 3600000*24*nDays);
    document.cookie = cookieName+"="+escape(cookieValue) + ";expires="+expire.toGMTString();
}

Live DEMO

返回页面时阅读cookie

感谢dunsmoreb

Thanks to dunsmoreb

我们可以使用此函数获取cookie，无耻地从这个问题偷了。

We can get the cookie using this function, shamelessly stolen from this question.

function readCookie(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;
}

然后我们需要在页面加载时选择值。以下代码将完成以下操作：

Then we need to select the value when the page loads. The following code will accomplish just that:

document.addEventListener('DOMContentLoaded', function() {
    var themeSelect = document.getElementById('ThemeSelect');
    var selectedTheme = readCookie('theme');

    themeSelect.value = selectedTheme;
    saveclass = saveclass ? saveclass : document.body.className;
    document.body.className = saveclass + ' ' + selectedTheme;
});

Live DEMO

这篇关于将下拉菜单选择保存在Cookie中？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！