从HTML 4规范:

如果一个表单包含多个提交按钮，只有激活 提交按钮成功。

这意味着如果有多个提交按钮且没有激活(单击)，则没有一个提交按钮会成功。

我认为这是有道理的:

想象一个有多个提交按钮的巨大表单。在顶部，有一个“删除这条记录”按钮，然后有很多输入，在底部有一个“更新这条记录”按钮。当用户在表单底部的字段中按Enter时，他/她永远不会怀疑他/她从顶部隐式地按下了“删除此记录”。

因此，我认为使用用户没有定义(点击)的第一个按钮或任何其他按钮都不是一个好主意。不过，浏览器当然也在这么做。

现在可以使用Flexbox解决这个问题:

HTML

<form>
    <h1>My Form</h1>
    <label for="text">Input:</label>
    <input type="text" name="text" id="text"/>

    <!-- Put the elements in reverse order -->
    <div class="form-actions">
        <button>Ok</button> <!-- Our default action is first -->
        <button>Cancel</button>
    </div>
</form>

CSS

.form-actions {
    display: flex;
    flex-direction: row-reverse; /* Reverse the elements inside */
}

解释

使用Flexbox，我们可以通过使用CSS规则:flex-direction: row-reverse来反转使用display: flex的容器中的元素顺序。这不需要CSS或隐藏元素。对于不支持Flexbox的旧浏览器，他们仍然得到一个可行的解决方案，但元素不会被反转。

Demo

http://codepen.io/Godwin/pen/rLVKjm

HTML 4并没有将其显式化。HTML 5规定第一个提交按钮必须是默认的:

4.10.21.2隐式提交 表单元素的默认按钮是按树顺序排列的第一个提交按钮，其表单所有者就是该表单元素。 如果用户代理支持让用户隐式提交表单 (例如，在某些平台上，在输入文本时按下“enter”键 控件隐式地提交表单)，然后为 表单，其默认按钮具有激活行为，但没有 禁用时，必须导致用户代理在此触发单击事件 默认按钮。

如果你想在保持视觉顺序的同时影响哪个是“第一个”，那么你可以采取一些方法。

一个屏幕外、无法对焦的按钮。

.hidden-default { 位置:绝对的; 左:-9999 px; ｝ < >形式 <输入名称= " text " > <button name="submit" value="wanted" class="hidden-default" tabindex="-1"></button> <button name="submit" value="not wanted">不是默认值 <button name="submit" value="wanted">看起来像默认的</button> > < /形式

Flexbox顺序:

.ordering { 显示:inline-flex; ｝ . ordered按钮{ 秩序:2; ｝ .订购按钮+按钮{ 顺序:1; ｝ < >形式 <输入名称= " text " > < div class = "排序" > <button name="submit" value="wanted">文件顺序第一个</button> <button name="submit" value="not wanted">在文档顺序中的第2位</button> . </button> . <button name="submit" value="not wanted < / div > > < /形式

If you submit the form via JavaScript (i.e., formElement.submit() or anything equivalent), then none of the submit buttons are considered successful and none of their values are included in the submitted data. (Note that if you submit the form by using submitElement.click() then the submit that you had a reference to is considered active; this doesn't really fall under the remit of your question since here the submit button is unambiguous but I thought I'd include it for people who read the first part and wonder how to make a submit button successful via JavaScript form submission. Of course, the form's onsubmit handlers will still fire this way whereas they wouldn't via form.submit() so that's another kettle of fish...)

If the form is submitted by hitting Enter while in a non-textarea field, then it's actually down to the user agent to decide what it wants here. The specifications don't say anything about submitting a form using the Enter key while in a text entry field (if you tab to a button and activate it using space or whatever, then there's no problem as that specific submit button is unambiguously used). All it says is that a form must be submitted when a submit button is activated. It's not even a requirement that hitting Enter in e.g. a text input will submit the form.

我相信Internet Explorer会选择在源代码中首先出现的提交按钮;我有一种感觉，Firefox和Opera会选择标签索引最低的按钮，如果没有其他定义，就会退回到第一个定义的按钮。关于提交是否具有非默认值属性IIRC，也存在一些复杂性。

The point to take away is that there is no defined standard for what happens here and it's entirely at the whim of the browser - so as far as possible in whatever you're doing, try to avoid relying on any particular behaviour. If you really must know, you can probably find out the behaviour of the various browser versions, but when I investigated this a while back there were some quite convoluted conditions (which of course are subject to change with new browser versions) and I'd advise you to avoid it if possible!

我的食谱:

<form>
    <input type=hidden name=action value=login> <!-- The magic! -->

    <input type=text name=email>
    <input type=text name=password>

    <input type=submit name=action value=login>
    <input type=submit name=action value="forgot password">
</form>

如果没有一个按钮被“单击”，它将发送默认隐藏字段。

如果单击其中一个，它具有优先级，其值将被传递。

从你的评论来看:

结果就是，如果你有 多个表单提交给同一个 脚本，你不能依赖于提交 按钮来区分它们。

我在每个表单中放入一个<input type="hidden" value="form_name" />。

如果使用JavaScript提交:将提交事件添加到表单，而不是将事件单击到按钮。精明的用户不会经常触碰鼠标。