ElementInternals: form property
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2023.
The form read-only property of the ElementInternals interface returns the HTMLFormElement associated with this element.
Value
An HTMLFormElement.
Examples
The following example shows a custom checkbox component inside a form with an ID of myForm.
Printing form.length to the console, gives us the value of HTMLFormElement.length.
html
<form id="myForm">
<custom-checkbox id="custom-checkbox"></custom-checkbox>
<custom-label for="custom-checkbox">Join newsletter</custom-label>
</form>
js
class CustomCheckbox extends HTMLElement {
static formAssociated = true;
#internals;
constructor() {
super();
this.#internals = this.attachInternals();
}
connectedCallback() {
console.log(this.#internals.form.length);
}
}
window.customElements.define("custom-checkbox", CustomCheckbox);
Specifications
| Specification |
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| HTML # dom-elementinternals-form |
Browser compatibility
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form
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Legend
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- Full support
- Full support