HTMLFormElement.length - Web APIs 编辑

The HTMLFormElement.length read-only property returns the number of controls in the <form> element. You can access the list of the form's controls using the elements property.

This includes both elements that are descendants of the <form> element as well as elements that are made members of the form using their form property.

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 elements, which makes it an excellent way to get at the elements most important when processing forms.

Syntax

numControls = form.length;

Value

numControls is the number of form controls within the <form>. This is the same as the number of the elements in the HTMLFormControlsCollection returned by the elements property.

Example

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

Specifications

Browser compatibility

BCD tables only load in the browser