自从我使用 jQuery 1.3+ 以来，除了一个定时测试正在使用它之外。另一个是我在 2000 年发现的普通 javascript。我停止了这条路线，因为它需要大约 150 秒来运行测试。我已经阅读了很多与选择单个元素相关的 jQuery 优化网页。 “#id”是使用它的最佳案例，但现在我遇到了在具有多个复选框列的相当大的表中选中一列中的所有复选框的问题。

我所做的是设置一个页面，创建 20,000 个表格行和两个复选框列。目标是检查第二列，看看花了多长时间，然后取消选中它们，看看花了多长时间。显然我们想要最短的时间。我只使用 IE6 和 7，在我的情况下，我的所有用户都会这样做。

你说 20,000 行？我也是这么说的，但这将要投入生产(不在我的手中)，现在改变已经太晚了。我只是想在时钟还剩 1 秒时抛出冰雹玛丽。此外，我了解到 input.chkbox 不是最快的选择器(对于 IE7)! :)

问题是，是否有更好的方法来执行此 jQuery 或其他操作？我希望它能在我的机器上运行不到半秒。

所以你不必重新输入我已经完成的所有废话这是我想出的测试内容:

更新了 2014 年 4 月早上，以包括进一步的计时赛:

<form id="form1" runat="server">
    <div>
        <a href="#" id="one">input[id^='chkbox'][type='checkbox']</a><br />
        <a href="#" id="two">#myTable tr[id^='row'] input[id^='chkbox'][type='checkbox']</a><br />
        <a href="#" id="three">#myTable tr.myRow input[id^='chkbox'][type='checkbox']</a><br />
        <a href="#" id="four">tr.myRow input[id^='chkbox'][type='checkbox']</a><br />
        <a href="#" id="five">input[id^='chkbox']</a><br />
        <a href="#" id="six">.chkbox</a><br />
        <a href="#" id="seven">input.chkbox</a><br />
        <a href="#" id="eight">#myTable input.chkbox</a><br />

        <a href="#" id="nine">"input.chkbox", "tr"</a><br />
        <a href="#" id="nine1">"input.chkbox", "tr.myRow"</a><br />
        <a href="#" id="nine2">"input.chkbox", "#form1"</a><br />
        <a href="#" id="nine3">"input.chkbox", "#myTable"</a><br />

        <a href="#" id="ten">input[name=chkbox]</a><br />
        <a href="#" id="ten1">"input[name=chkbox]", "tr.myRow"</a><br />
        <a href="#" id="ten2">"input[name=chkbox]", "#form1"</a><br />
        <a href="#" id="ten3">"input[name=chkbox]", "#myTable"</a><br />

        <a href="#" id="ten4">"input[name=chkbox]", $("#form1")</a><br />
        <a href="#" id="ten5">"input[name=chkbox]", $("#myTable")</a><br />

        <a href="#" id="eleven">input[name='chkbox']:checkbox</a><br />
        <a href="#" id="twelve">:checkbox</a><br />
        <a href="#" id="twelve1">input:checkbox</a><br />
        <a href="#" id="thirteen">input[type=checkbox]</a><br />

        <div>
            <input type="text" id="goBox" /> <button id="go">Go!</button>
            <div id="goBoxTook"></div>
        </div>

        <table id="myTable">
            <tr id="headerRow"><th>Row #</th><th>Checkboxes o' fun!</th><th>Don't check these!</th></tr>
            <% for(int i = 0; i < 20000;i++) { %>
            <tr id="row<%= i %>" class="myRow">
                <td><%= i %> Row</td>
                <td>
                    <input type="checkbox" id="chkbox<%= i %>" name="chkbox" class="chkbox" />
                </td>
                <td>
                    <input type="checkbox" id="otherBox<%= i %>" name="otherBox" class="otherBox" />
                </td>
            </tr>
            <% } %>
        </table>
    </div>

    <script type="text/javascript" src="<%= ResolveUrl(" ~/") %>Javascript/jquery.1.3.1.min.js"></script>
    <script type="text/javascript">

        $(function () {
            function run(selectorText, el) {
                var start = new Date();
                $(selectorText).attr("checked", true);
                var end = new Date();
                var timeElapsed = end - start;
                $(el).after("<br />Checking Took " + timeElapsed + "ms");

                start = new Date();
                $(selectorText).attr("checked", false);
                end = new Date();
                timeElapsed = end - start;
                $(el).after("<br />Unchecking Took " + timeElapsed + "ms");
            }

            function runWithContext(selectorText, context, el) {
                var start = new Date();
                $(selectorText, context).attr("checked", true);
                var end = new Date();
                var timeElapsed = end - start;
                $(el).after("<br />Checking Took " + timeElapsed + "ms");

                start = new Date();
                $(selectorText, context).attr("checked", false);
                end = new Date();
                timeElapsed = end - start;
                $(el).after("<br />Unchecking Took " + timeElapsed + "ms");
            }

            $("#one").click(function () {
                run("input[id^='chkbox'][type='checkbox']", this);
            });

            $("#two").click(function () {
                run("#myTable tr[id^='row'] input[id^='chkbox'][type='checkbox']", this);
            });

            $("#three").click(function () {
                run("#myTable tr.myRow input[id^='chkbox'][type='checkbox']", this);
            });

            $("#four").click(function () {
                run("tr.myRow input[id^='chkbox'][type='checkbox']", this);
            });

            $("#five").click(function () {
                run("input[id^='chkbox']", this);
            });

            $("#six").click(function () {
                run(".chkbox", this);
            });

            $("#seven").click(function () {
                run("input.chkbox", this);
            });

            $("#eight").click(function () {
                run("#myTable input.chkbox", this);
            });

            $("#nine").click(function () {
                runWithContext("input.chkbox", "tr", this);
            });


            $("#nine1").click(function () {
                runWithContext("input.chkbox", "tr.myRow", this);
            });
            $("#nine2").click(function () {
                runWithContext("input.chkbox", "#form1", this);
            });
            $("#nine3").click(function () {
                runWithContext("input.chkbox", "#myTable", this);
            });

            $("#ten").click(function () {
                run("input[name=chkbox]", this);
            });

            $("#ten1").click(function () {
                runWithContext("input[name=chkbox]", "tr.myRow", this);
            });

            $("#ten2").click(function () {
                runWithContext("input[name=chkbox]", "#form1", this);
            });

            $("#ten3").click(function () {
                runWithContext("input[name=chkbox]", "#myTable", this);
            });

            $("#ten4").click(function () {
                runWithContext("input[name=chkbox]", $("#form1"), this);
            });

            $("#ten5").click(function () {
                runWithContext("input[name=chkbox]", $("#myTable"), this);
            });

            $("#eleven").click(function () {
                run("input[name='chkbox']:checkbox", this);
            });

            $("#twelve").click(function () {
                run(":checkbox", this);
            });

            $("#twelve1").click(function () {
                run("input:checkbox", this);
            });

            $("#thirteen").click(function () {
                run("input[type=checkbox]", this);
            });

            $('#go').click(function () {
                run($('#goBox').val(), this);
            });
        });
    </script>
</form>

最佳答案

input[name=chkbox] 是我机器上 IE7 下最快的 jQuery 选择器。

Unchecking Took 2453ms
Checking Took 2438ms
Unchecking Took 2438ms
Checking Took 2437ms
Unchecking Took 2453ms
Checking Took 2438ms

input.chkbox 和...

Unchecking Took 2813ms
Checking Took 2797ms
Unchecking Took 2797ms
Checking Took 2797ms
Unchecking Took 2813ms
Checking Took 2797ms

input:checkbox.chkbox 似乎绑定(bind)

Unchecking Took 2797ms
Checking Took 2797ms
Unchecking Took 2813ms
Checking Took 2781ms

.chkbox 几乎是 input.chkbox 的两倍

Unchecking Took 4031ms
Checking Took 4062ms
Unchecking Took 4031ms
Checking Took 4062ms

javascript for 循环是迄今为止最糟糕的出现在:

Checking Took 149797ms

150 秒!它也锁定了浏览器。这让我对 jQuery 印象深刻。老实说，我没想到会这么慢。可能是因为我传递了它必须找到的每个单独的元素......

这对我来说也很有趣:

输入[id^='chkbox']

Unchecking Took 3031ms
Checking Took 3016ms

花费的时间少于:

输入[id^='chkbox'][type='checkbox']

Unchecking Took 3375ms
Checking Took 3344ms

我想既然我发布了更多的过滤器，它会更快。不!

为复选框指定更多路径会使速度变慢:

#myTable tr[id^='row'] input[id^='chkbox'][type='checkbox']

Checking Took 10422ms

它甚至没有运行第二次取消检查，因为它询问我是否要继续在我的计算机上运行脚本。疯狂的! :P

4 月 14 日上午更新:

有人提出设置上下文:我实际上做了其中的一些，这让我大吃一惊，而且与很多人在网络上所说的在 IE7 上这些速度较慢相反!以下是我使用几个不同的上下文指定的时间与上面更快的选择器配对:

"input.chkbox", "tr"

Checking Took 8546ms

"input.chkbox", "tr.myRow"

Checking Took 8875ms

"input.chkbox", "#form1"

Unchecking Took 3032ms
Checking Took 3000ms

"input.chkbox", "#myTable"

Unchecking Took 2906ms
Checking Took 2875ms

当前获胜者(仍然):input[name=chkbox]

Unchecking Took 2469ms
Checking Took 2453ms

"输入[name=chkbox]", "tr.myRow"

Checking Took 9547ms

"输入[name=chkbox]", "#form1"

Unchecking Took 3140ms
Checking Took 3141ms

"输入[name=chkbox]", "#myTable"

Unchecking Took 2985ms
Checking Took 2969ms

2 月 4 日上午更新 2

在我注意到与 http://beardscratchers.com/journal/jquery-its-all-about-context 的语法差异后，我想我可能会有一个更好的.看起来这些与它们给出的时间稍微好一些，但仍然没有击败非上下文选择器 - 该死的。

"输入[name=chkbox]", $("#form1")

Unchecking Took 3078ms
Checking Took 3000ms
Unchecking Took 3078ms
Checking Took 3016ms

"输入[name=chkbox]", $("#myTable")

Unchecking Took 2938ms
Checking Took 2906ms
Unchecking Took 2938ms
Checking Took 2921ms

4 月 14 日上午更新 3

Russ 想让我试试这些，他们取消/选择了所有框，但这又很有趣:

:复选框

Unchecking Took 8328ms
Checking Took 6250ms

输入:复选框

Unchecking Took 5016ms
Checking Took 5000ms

->最快？!？! 输入[type=checkbox]

Unchecking Took 4969ms
Checking Took 4938ms

第三个是最快的这一事实非常有趣，因为这与我的想法相反。为什么(至少对于 IE7) :checkbox 不使用 type=checkbox 来获得更快的时间？这些分数非常接近，但检查时间减少了 62 毫秒。另外，为什么前两个完全不同？除了可以带复选框的输入之外，是否还有其他元素？

关于javascript - 选择大量复选框并取消/选择它们的最快方法是什么？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/745720/