Question

以下代码的灵感来自http://ignorethecode.net/blog/2010/04/20/footnotes/：当您将光标移到脚注符号上时，脚注会显示为工具提示。

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>footnote demo</title>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
</head>
<body>

<p>Baryonyx was a theropod dinosaur of the early Cretaceous Period, about 130–125 million years ago<a href="#fn1" class="footnoteRef" id="fnref1"><sup>1</sup></a>. An identifying specimen of the genus was discovered in 1983 in Surrey, England; fragmentary specimens<a href="#fn2" class="footnoteRef" id="fnref2"><sup>2</sup></a> were later discovered in other parts of the United Kingdom and Iberia. Meaning "heavy claw", Baryonyx refers to the animal's very large claw (31 cm or 12 in) on the first finger. The 1983 specimen<a href="#fn3" class="footnoteRef" id="fnref3"><sup>3</sup></a> is one of the most complete theropod skeletons from the UK, and its discovery attracted media attention.</p>

<div class="footnotes">
<hr>
<ol>
<li id="fn1"><p>Baryonyx caught and held its prey primarily with its strong forelimbs and large claws.<a href="#fnref1">↩</a></p></li>
<li id="fn2"><p>The creature lived near bodies of water, in areas where other theropod, ornithopod, and sauropod dinosaurs have also been found. <a href="#fnref2">↩</a></p></li>
<li id="fn3"><p>It had a long, low, bulbous snout and narrow, many-toothed jaws, which have been compared to gharial jaws.<a href="#fnref3">↩</a></p></li>
</ol>
</div>

<script>
var removeElements = function(text, selector) {
    var wrapped = $("<div>" + text + "</div>");
    wrapped.find(selector).remove();
    return wrapped.html();
}

var $fRef = $(".footnoteRef");
for(var i=0; i<$fRef.length; i++) {
    var sup = $fRef.children("sup")[i];
    //var sup = $fRef[i].children("sup");
    //var sup = $fRef.eq(i).children("sup");
    //var sup = $fRef.get(i).children("sup");
    //var sup = $($fRef[i]).children("sup");
    //debugger;
    sup.setAttribute('fnID',i);
    sup.onmouseover = function(event) {
        var fnTip = document.getElementById('fnTip');
        if(fnTip) fnTip.parentNode.removeChild(fnTip);
        var pTip = document.createElement('div');
        var fnT = document.getElementById($fRef[this.getAttribute('fnID')].getAttribute("href").substring(1)).innerHTML;
        pTip.innerHTML = removeElements(fnT,"a");
        pTip.id = 'fnTip';
        pTip.style.position = 'absolute';
        pTip.style.left = (event.pageX - 180) + 'px';
        pTip.style.top = (event.pageY + 20) + 'px';
        pTip.style.width = '360px';
        pTip.style.textIndent = '2em';
        pTip.style.textAlign = 'left';
        pTip.style.backgroundColor = '#FFFFE0';
        pTip.style.border = '1px solid #636363';
        pTip.style.padding = '5px';
        pTip.style.fontSize = '12px';
        pTip.style.lineHeight = '1.8';
        pTip.style.borderRadius =  '5px';
        document.body.appendChild(pTip);
    };

    sup.onmouseout = function(event) {
        var fnTip = document.getElementById('fnTip');
        if(fnTip) fnTip.parentNode.removeChild(fnTip);
    };
}

</script>

</body>
</html>

我的问题是，var sup = $fRef.children("sup")[i];行应该是var sup = $fRef[i].children("sup");，或.children() does not work on specified index of jquery return之后。但是，这些方式（代码中的行被注释）都不起作用。请解释为什么var sup = $fRef.children("sup")[i];正在运行，而其他人无效？

Answer 1

var sup = $fRef.children("sup")[i];
获取$ fRef的子集合中的第i个元素;
所有其他方法都处理$ fRef集合的第i个元素：
var sup = $fRef[i].children("sup");
尝试在jQuery集合$ fRef的第i个元素上调用函数children，但该元素是经典的Dom元素，因此它没有任何子元素方法。
var sup = $fRef.eq(i).children("sup");
与2相同但正确，因为eq将返回一个jQuery对象。它检索$ rFref
var sup = $fRef.get(i).children("sup");
get方法与索引的作用相同：它获取dom对象，因此它也不起作用。
var sup = $($fRef[i]).children("sup");
当你在dom元素中重新包装html集合时，它也将工作为3。虽然

jQuery：array [i] .children（）不是函数

1 个答案: