HTML表单上的默认提交按钮是如何确定的?

如果提交了表单，但不是通过任何特定的按钮，例如

按Enter键使用JS中的HTMLFormElement.submit()

浏览器应该如何确定多个提交按钮(如果有的话)中的哪一个作为按下的按钮呢?

这在两个层面上很重要:

调用附加到提交按钮的onclick事件处理程序数据发送回web服务器

到目前为止，我的实验表明:

当按Enter键时，Firefox、Opera和Safari使用表单中的第一个提交按钮当按Enter键时，IE要么使用第一个提交按钮，要么根本不使用，这取决于我还没能弄清楚的条件所有这些浏览器都不使用JS提交

标准是怎么说的?

如果有帮助的话，下面是我的测试代码(PHP只与我的测试方法相关，与我的问题本身无关)

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
                      "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Test</title>
</head>

<body>

<h1>Get</h1>
<dl>
<?php foreach ($_GET as $k => $v) echo "<dt>$k</dt><dd>$v</dd>"; ?>
</dl>

<h1>Post</h1>
<dl>
<?php foreach ($_POST as $k => $v) echo "<dt>$k</dt><dd>$v</dd>"; ?>
</dl>

<form name="theForm" method="<?php echo isset($_GET['method']) ? $_GET['method'] : 'get'; ?>" action="<?php echo $_SERVER['SCRIPT_NAME']; ?>">
    <input type="text" name="method" />
    <input type="submit" name="action" value="Button 1" onclick="alert('Button 1'); return true" />
    <input type="text" name="stuff" />
    <input type="submit" name="action" value="Button 2" onclick="alert('Button 2'); return true" />
    <input type="button" value="submit" onclick="document.theForm.submit();" />
</form>

</body></html>

当前回答

Andrezj的答案几乎是完美的……但这里有一个简单的跨浏览器解决方案。

取这样的形式:

<form>
    <input/>
    <button type="submit" value="some non-default action"/>
    <button type="submit" value="another non-default action"/>
    <button type="submit" value="yet another non-default action"/>

    <button type="submit" value="default action"/>
</form>

然后重构为:

<form>
    <input/>

    <button style="overflow: visible !important; height: 0 !important; width: 0 !important; margin: 0 !important; border: 0 !important; padding: 0 !important; display: block !important;" type="submit" value="default action"/>

    <button type="submit" value="some non-default action"/>
    <button type="submit" value="another non-default action"/>
    <button type="submit" value="yet another non-default action"/>
    <button type="submit" value="still another non-default action"/>

    <button type="submit" value="default action"/>
</form>

由于W3C规范指出多个提交按钮是有效的，但忽略了关于用户代理应该如何处理它们的指导，所以浏览器制造商只能按照他们认为合适的方式来实现。我发现他们要么提交表单中的第一个提交按钮，要么在当前有焦点的表单字段之后提交下一个提交按钮。

不幸的是，简单地添加一个显示样式:none;这是行不通的，因为W3C规范指出任何隐藏元素都应该从用户交互中排除。所以把它藏在众目睽睽之下吧!

上面是我最终投入生产的解决方案示例。按enter键触发默认表单提交，即使在DOM中出现其他非默认值并在默认提交按钮之前也是如此。与显式用户输入的鼠标/键盘交互的额外好处，同时避免JavaScript处理程序。

Note: tabbing through the form will not display focus for any visual element yet will still cause the invisible button to be selected. To avoid this issue, simply set tabindex attributes accordingly and omit a tabindex attribute on the invisible submit button. While it may seem out of place to promote these styles to !important, they should prevent any framework or existing button styles from interfering with this fix. Also, those inline styles are definitely poor form, but we're proving concepts here... not writing production code.

2012-02-28 22:59:57

其他回答

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

2009-05-29 10:31:09

<form onsubmit="alert('submit');return false;">
    <input name="username">
    <input name="password" type="password">
    <button onclick="if(document.activeElement === this){alert('button 1');}else{default_submit.click();}return false;">button 1</button>
    <button onclick="if(document.activeElement === this){alert('button 2');}else{default_submit.click();}return false;">button 2</button>
    <input id="default_submit" type="submit">
</form>

如果从文本输入中按Enter，则该按钮将不会聚焦。然后我们忽略这个点击，然后点击默认提交，但是如果你用鼠标点击按钮，它将被聚焦，然后我们应用这个点击。

演示:https://codepen.io/remon-reffat/pen/mdRaXbp

2020-12-06 11:33:58

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!

2009-05-29 10:41:13

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。

2011-04-07 08:29:08