HTMLFormElement.length

在此页

句法
范例
规范
浏览器兼容性
相关话题

HTMLFormElement.length read-only property returns the number of controls in the <form> 元素。 You can access the list of the form's controls using the 元素 特性。

This includes both elements that are descendents of the <form> element as well as elements that are made members of the form using their form 特性。

The elements included by HTMLFormElement.elements and HTMLFormElement.length are the following:

<button>
<fieldset>
<input> (with the exception that any whose type is "image" are omitted for historical reasons)
<object>
<output>
<select>
<textarea>

No other elements are included in the list returned by 元素 , which makes it an excellent way to get at the elements most important when processing forms.

句法

numControls = form.length;

值

numControls is the number of form controls within the <form> . This is the same as the number of the elements in the HTMLFormControlsCollection 返回通过 元素 特性。

范例

if (document.getElementById('form1').length > 1) {
  // more than one form control here
}

规范

规范	状态	注释
HTML 实时标准 The definition of 'HTMLFormElement: length' in that specification.	实时标准

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`length`	Chrome Yes	Edge 12	Firefox Yes	IE ?	Opera Yes	Safari Yes	WebView Android Yes	Chrome Android Yes	Firefox Android Yes	Opera Android Yes	Safari iOS Yes	Samsung Internet Android Yes

图例

完整支持
兼容性未知 ?

元数据

最后修改： Jan 10, 2020

在此页

句法

值

范例

规范

浏览器兼容性

图例

相关话题