files/en-us/web/api/htmlformelement/index.md
{{APIRef("HTML DOM")}}
The HTMLFormElement interface represents a {{HTMLElement("form")}} element in the DOM. It allows access to—and, in some cases, modification of—aspects of the form, as well as access to its component elements.
{{InheritanceDiagram}}
This interface also inherits properties from its parent, {{domxref("HTMLElement")}}.
accept-charset HTML attribute.action HTML attribute, containing the URI of a program that processes the information submitted by the form.autocomplete HTML attribute, indicating whether the controls in this form can have their values automatically populated by the browser.enctype HTML attribute, indicating the type of content that is used to transmit the form to the server. Only specified values can be set. The two properties are synonyms.long reflecting the number of controls in the form.name HTML attribute, containing the name of the form.novalidate HTML attribute, indicating whether the form should not be validated.method HTML attribute, indicating the HTTP method used to submit the form. Only specified values can be set.rel HTML attribute, which represents what kinds of links the form creates as a space-separated list of enumerated values.rel HTML attribute, as a list of tokens.target HTML attribute, indicating where to display the results received from submitting the form.Named inputs are added to their owner form instance as properties, and can overwrite native properties if they share the same name (e.g., a form with an input named action will have its action property return that input instead of the form's action HTML attribute).
This interface also inherits methods from its parent, {{domxref("HTMLElement")}}.
true if the element's child controls are subject to constraint validation and satisfy those constraints; returns false if some controls do not satisfy their constraints. Fires an event named {{domxref("HTMLInputElement/invalid_event", "invalid")}} at any control that does not satisfy its constraints; such controls are considered invalid if the event is not canceled. It is up to the programmer to decide how to respond to false.true if the element's child controls satisfy their validation constraints. When false is returned, cancelable {{domxref("HTMLInputElement/invalid_event", "invalid")}} events are fired for each invalid child and validation problems are reported to the user.Listen to these events using addEventListener(), or by assigning an event listener to the oneventname property of this interface.
formdata event fires after the entry list representing the form's data is constructed.reset event fires when a form is reset.submit event fires when a form is submitted.To obtain an HTMLFormElement object, you can use a CSS selector with {{domxref("Document.querySelector", "querySelector()")}}, or you can get a list of all of the forms in the document using its {{domxref("Document.forms", "forms")}} property.
{{domxref("Document.forms")}} returns an array of HTMLFormElement objects listing each of the forms on the page. You can then use any of the following syntaxes to get an individual form:
document.forms[index]
index into the array of forms.document.forms[id]
id.document.forms[name]
name attribute's value is name.You can access the list of the form's data-containing elements by examining the form's {{domxref("HTMLFormElement.elements", "elements")}} property. This returns an {{domxref("HTMLFormControlsCollection")}} listing all of the form's user data entry elements, both those which are descendants of the <form> and those which are made members of the form using their form attributes.
You can also get the form's element by using its name attribute as a key of the form, but using elements is a better approach—it contains only the form's elements, and it cannot be mixed with other attributes of the form.
Some names will interfere with JavaScript access to the form's properties and elements.
For example:
<input name="id"> will take precedence over <form id="…">. This means that form.id will not refer to the form's id, but to the element whose name is "id". This will be the case with any other form properties, such as <input name="action"> or <input name="post">.<input name="elements"> will render the form's elements collection inaccessible. The reference form.elements will now refer to the individual element.To avoid such problems with element names:
elements collection to avoid ambiguity between an element name and a form property."elements" as an element name.If you are not using JavaScript, this will not cause a problem.
The elements included by HTMLFormElement.elements and HTMLFormElement.length are the following:
type is "image" are omitted for historical reasons)No other elements are included in the list returned by elements, which makes it an excellent way to get at the most important elements when processing forms.
Creating a new form element, modifying its attributes, then submitting it:
const f = document.createElement("form"); // Create a form
document.body.appendChild(f); // Add it to the document body
f.action = "/cgi-bin/some.cgi"; // Add action and method attributes
f.method = "POST";
f.submit(); // Call the form's submit() method
Extract information from a <form> element and set some of its attributes:
<form name="formA" action="/cgi-bin/test" method="post">
<p>Press "Info" for form details, or "Set" to change those details.</p>
<p>
<button type="button" id="info">Info</button>
<button type="button" id="set-info">Set</button>
<button type="reset">Reset</button>
</p>
<textarea id="form-info" rows="15" cols="20"></textarea>
</form>
document.getElementById("info").addEventListener("click", () => {
// Get a reference to the form via its name
const f = document.forms["formA"];
// The form properties we're interested in
const properties = [
"elements",
"length",
"name",
"charset",
"action",
"acceptCharset",
"action",
"enctype",
"method",
"target",
];
// Iterate over the properties, turning them into a string that we can display to the user
const info = properties
.map((property) => `${property}: ${f[property]}`)
.join("\n");
// Set the form's <textarea> to display the form's properties
document.forms["formA"].elements["form-info"].value = info; // document.forms["formA"]['form-info'].value would also work
});
document.getElementById("set-info").addEventListener("click", (e) => {
// Get a reference to the form via the event target
// e.target is the button, and .form is the form it belongs to
const f = e.target.form;
// Argument should be a form element reference.
f.action = "a-different-url.cgi";
f.name = "a-different-name";
});
Submit a <form> into a new window:
<form action="test.php" target="_blank">
<p>
<label>First name: <input type="text" name="first-name" /></label>
</p>
<p>
<label>Last name: <input type="text" name="last-name" /></label>
</p>
<p>
<label><input type="password" name="pwd" /></label>
</p>
<fieldset>
<legend>Pet preference</legend>
<p>
<label><input type="radio" name="pet" value="cat" /> Cat</label>
</p>
<p>
<label><input type="radio" name="pet" value="dog" /> Dog</label>
</p>
</fieldset>
<fieldset>
<legend>Owned vehicles</legend>
<p>
<label
><input type="checkbox" name="vehicle" value="Bike" />I have a
bike</label
>
</p>
<p>
<label
><input type="checkbox" name="vehicle" value="Car" />I have a car</label
>
</p>
</fieldset>
<p><button>Submit</button></p>
</form>
{{Specifications}}
{{Compat}}