怎样保存选择的图片呢？

//网上找来的读写coolie的代码
//写cookies函数作者：翟振凯
function SetCookie(name,value)//两个参数，一个是cookie的名子，一个是值
{
    var Days = 30; //此 cookie 将被保存 30 天
    var exp  = new Date();    //new Date("December 31, 9998");
    exp.setTime(exp.getTime() + Days*24*60*60*1000);
    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}
function getCookie(name)//取cookies函数
{
    var arr = document.cookie.match(new RegExp("(^| )"+name+"=([^;]*)(;|$)"));
     if(arr != null) return unescape(arr[2]); return null;}//这个函数改一下
function showLogo(flag)
{
    if(flag>logo.lenth)
        flag = 0;
    var pic = document.getElementById("logo");
    pic.src = logo[flag];
    SetCookie("logo",logo[flag])
} window.onload = function()
{
    var url = getCookie("logo");
    if(url==null)
        url = "http://www.sogou.com/image/slogo.gif";//默认图片    var pic = document.getElementById("logo");
    pic.src = url;
}

解决方案 »

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首先感谢您的回复！
但是我在程序中用了shadowbox，所以onload函数不能打开shadowbox,改用以下网上的解决办法后，图片却不能更换了！
function ttt()
{
    var url = getCookie("logo");
    if(url==null)
        url = "http://www.sogou.com/image/slogo.gif";//默认图片    var pic = document.getElementById("logo");
    pic.src = url;
}

function addLoadEvent(func) {
var oldonload = window.onload;
if (typeof window.onload != ‘function’) {
window.onload = func;
}
else {
window.onload = function() {
oldonload();
func();
};
}
}addLoadEvent(ttt);能否有办法不用onload方法解决cookie，比如写入数据库能行吗？但是写入数据库需要转换js变量的值为php的变量值，
尝试了一下，不爽！
还请您多指点一下！
万分感谢！
即使不用shadowbox,采用其他的弹出层程序，也能更改图片，但是cookie无效！请您看看：
<html> <head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title>LIGHTBOX EXAMPLE</title>
        <style>
        .black_overlay{
            display: none;
            position: absolute;
            top: 0%;
            left: 0%;
            width: 100%;
            height: 100%;
            background-color: black;
            z-index:1001;
            -moz-opacity: 0.8;
            opacity:.80;
            filter: alpha(opacity=80);
        }
        .white_content {
            display: none;
            position: absolute;
            top: 25%;
            left: 25%;
            width: 50%;
            height: 50%;
            padding: 16px;
            border: 16px solid orange;
            background-color: white;
            z-index:1002;
            overflow: auto;
        }
    </style>
<script type="text/javascript">
var logo = [
"http://www.google.cn/intl/zh-CN/images/logo_cn.gif",
"http://www.baidu.com/img/baidu_logo.gif",
"http://www.sogou.com/image/slogo.gif"
]; function fun()
{
    var op = document.getElementById("op");
    if(op.style.display=="none")
        op.style.display="block";
    else
        op.style.display="none";
} function SetCookie(name,value)//两个参数，一个是cookie的名子，一个是值
{
    var Days = 30; //此 cookie 将被保存 30 天
    var exp  = new Date();    //new Date("December 31, 9998");
    exp.setTime(exp.getTime() + Days*24*60*60*1000);
    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}
function getCookie(name)//取cookies函数
{
    var arr = document.cookie.match(new RegExp("(^| )"+name+"=([^;]*)(;|$)"));
     if(arr != null) return unescape(arr[2]); return null;}//这个函数改一下
function showLogo(flag)
{
    if(flag>logo.lenth)
        flag = 0;
    var pic = document.getElementById("logo");
    pic.src = logo[flag];
    SetCookie("logo",logo[flag])
} window.onload = function()
{
    var url = getCookie("logo");
    if(url==null)
        url = "http://www.sogou.com/image/slogo.gif";//默认图片    var pic = document.getElementById("logo");
    pic.src = url;
}
</script>
    </head>
    <body>
        <p><a href = "javascript:void(0)" onclick = "document.getElementById('light').style.display='block';document.getElementById('fade').style.display='block'">
<img src="http://www.sogou.com/image/slogo.gif" id="logo" onclick="fun()" /> </a></p>

        <div id="light" class="white_content">

This is the lightbox content. <br />
<div id="op" style="border:red solid 1px; display:none;">
    <button onclick="showLogo(0)">google </button>
    <button onclick="showLogo(1)">baidu </button>
    <button onclick="showLogo(2)">sogou </button>
</div>
<br />
<a href = "javascript:void(0)" onclick = "document.getElementById('light').style.display='none';document.getElementById('fade').style.display='none'">Close</a>
</div>
        <div id="fade" class="black_overlay"></div>
    </body>
</html>多谢
哦，仔细看了一下，解决了问题！上面的例子没问题，暂时用这个代替shadowbox吧。多谢您varlj！