如何选择< td> < table>用javascript？

问题描述：

我知道这是一个非常简单的问题，但我无法在任何地方找到答案。只有答案是使用jQuery，而不是纯JS。我已经尝试了下面的代码，它不起作用。我不知道为什么。

I know this is very easy question, but I couldn't find the answer anywhere. Only answers are the ones using jQuery, not pure JS. I've tried the code below and it doesn't work. I don't know why.

var t = document.getElementById("table"),
    d = t.getElementsByTagName("tr"),
    r = d.getElementsByTagName("td");

这也不起作用：

var t = document.getElementById("table"),
    d = t.getElementsByTagName("tr"),
    r = d.childNodes;

我做错了什么？这样做的最佳方式是什么？

What am I doing wrong? What is the best way to do this?

编辑：
我确实有我的表格的id。我知道，我很傻。这就是我的HTML外观：

I indeed have the id of my table table. Preety silly I know. This is how my HTML looks:

<table id="table">
            <tr>
                <td id="c1">1</td>
                <td id="c2">2</td>
                <td id="c3">3</td>
            </tr>
            <tr>
                <td id="b1">4</td>
                <td id="b2">5</td>
                <td id="b3">6</td>
            </tr>
            <tr>
                <td id="a1">7</td>
                <td id="a2">8</td>
                <td id="a3">9</td>
            </tr>
</table>

更清楚地解释我的意图>我希望制作一个tic tac toe游戏。对于初学者，我希望点击< td>并且能够提取特定的< td>。如何最有效地做到这一点？

To explain my intentions more clearly > I wish to make a tic tac toe game. For starters, I wish to click on the < td > and be able extract the id of that particular < td >. How to do it most efficiently?

答

这个 d = t.getElementsByTagName（tr）和此 r = d.getElementsByTagName（td）都是数组。 getElementsByTagName 会返回元素集合，即使在您的匹配项中只找到一个元素。

This d = t.getElementsByTagName("tr") and this r = d.getElementsByTagName("td") are both arrays. The getElementsByTagName returns an collection of elements even if there's just one found on your match.

所以你必须使用像这样：

So you have to use like this:

var t = document.getElementById("table"), // This have to be the ID of your table, not the tag
    d = t.getElementsByTagName("tr")[0],
    r = d.getElementsByTagName("td")[0];

将数组的索引放在想要访问的对象上。

Place the index of the array as you want to access the objects.

注意 getElementById ，因为名称只是得到匹配id的元素，所以你的表必须像&lt ; table id ='table'> 和 getElementsByTagName 通过标记获取。

Note that getElementById as the name says just get the element with matched id, so your table have to be like <table id='table'> and getElementsByTagName gets by the tag.

编辑：

好了，继续这篇文章，我想你可以这样做：

Well, continuing this post, I think you can do this:

var t = document.getElementById("table");
var trs = t.getElementsByTagName("tr");
vat tds = null;

for (var i=0; i<trs.length; i++)
{
    tds = trs[i].getElementsByTagName("td");
    for (var n=0; n<trs.length;n++)
    {
        tds[n].onclick=function() { alert(this.id); }
    }
}

试试吧！

如何选择< td> < table>用javascript？

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