Question

我是一名javascript程序员。我正在尝试创建类似于Lightbox 2的东西，但更简单。我想从头开始自己做的唯一原因是我可以学习。但是，我一直被困在显示图像的最后一个关键部分。我相信问题在于我尝试使用onclick并赋值给匿名函数： elem [i] .onclick = function（）{liteBoxFocus（imgSource，imgTitle）; return false;}; 即可。如果您运行我的代码并尝试点击谷歌徽标，它将调出雅虎徽标和标题，而不是谷歌的徽标和标题。但是，当你点击雅虎徽标它工作正常，所以似乎匿名函数只适用于最后一个循环。在此先感谢!!!

为方便起见，我将整个CSS / JS / XHTML放在一个页面中。

<html>
<head>
<title>Erik's Script</title>

<style type="text/css">
#liteBoxBg, #liteBox {
    display: none;
}

#liteBoxBg {
    background-color: #000000;
    height: 100%;
    width:100%;
    margin:0px;
    position: fixed;
    left:0px;
    top: 0px;
    filter:alpha(opacity=80);
    -moz-opacity:0.8;
    -khtml-opacity: 0.8;
    opacity: 0.8;
    z-index: 40;
}

#liteBox {
    background-color:#fff;
    padding: 10px;
    position:absolute;
    top:10%;
    border: 1px solid #ccc;
    width:auto;
    text-align:center;
    z-index: 50;
}
</style>

<script type="text/javascript">

window.onload = start;

function start(){

    var imgTitle = "No title";
    var imgSource;
    var elem = document.getElementsByTagName("a");
    var i;

    //Dynamically insert the DIV's to produce effect
    var newDiv = document.createElement('div');
    newDiv.setAttribute("id", "liteBox");
    document.getElementsByTagName("body")[0].appendChild(newDiv);

    newDiv = document.createElement('div');
    newDiv.setAttribute("id", "liteBoxBg");
    document.getElementsByTagName("body")[0].appendChild(newDiv);

    //Check those anchors with rel=litebox
    for(i = 0;i < elem.length;i++){
        if(elem[i].rel == "litebox"){
            imgSource = elem[i].href.toString();
            imgTitle = elem[i].title;
            elem[i].childNodes[0].style.border="0px solid #fff";
            elem[i].onclick = function (){liteBoxFocus(imgSource,imgTitle); return false;};
        }
    }

    //When foreground is clicked, close lite box
    document.getElementById("liteBoxBg").onclick = liteBoxClose;
}

//Brings up the image with focus
function liteBoxFocus(source,title){
    document.getElementById("liteBox").style.display = "block";
    document.getElementById("liteBox").innerHTML = "<h1>" + title + "</h1>" +
                                                   "<img src='" + source + "'/><br />" +
                                                   "<a href='#' onclick='liteBoxClose();'><img src='images/litebox_close.gif' border='0' alt='close'/></a>";
    document.getElementById("liteBoxBg").style.display = "block";
}

//closes lite box
function liteBoxClose(){
    document.getElementById("liteBox").style.display = "none";
    document.getElementById("liteBoxBg").style.display = "none";
    return false;
}

</script>



</head>

<body>

<a href="http://www.google.com/intl/en_ALL/images/logo.gif" rel="litebox" title="Google Logo"><img src="http://www.google.com/intl/en_ALL/images/logo.gif" alt="" /></a>

<a href="
http://www.barbariangroup.com/assets/users/bruce/images/0000/4121/yahoo_logo.jpg" rel="litebox" title="Yahooo Logo"><img src="
http://www.barbariangroup.com/assets/users/bruce/images/0000/4121/yahoo_logo.jpg" alt="" /></a>



</body>
</html>

Answer 1

您的事件处理程序形成一个闭包，记住指向封闭范围中变量的“实时”指针。因此，当它们实际执行时，它们具有最后一个值imgSource和imgTitle。

相反，您可以使用此模式来本地化变量值。这将在每次调用getClickHandler时创建源和标题的副本。因此，返回的函数会记住循环迭代中的值。

//Check those anchors with rel=litebox
for(i = 0;i < elem.length;i++){
    if(elem[i].rel == "litebox"){
        imgSource = elem[i].href.toString();
        imgTitle = elem[i].title;
        elem[i].childNodes[0].style.border="0px solid #fff";
        elem[i].onclick = getClickHandler(imgSource, imgTitle);
    }
}


//Brings up the image with focus
function getClickHandler(source,title){
    return function() {
        document.getElementById("liteBox").style.display = "block";
        document.getElementById("liteBox").innerHTML = "<h1>" + title + "</h1>" +
                                               "<img src='" + source + "'/><br />" +
                                               "<a href='#' onclick='liteBoxClose();'><img src='images/litebox_close.gif' border='0' alt='close'/></a>";
        document.getElementById("liteBoxBg").style.display = "block";
    }
}

javascript onclick，匿名函数

1 个答案: