I'd like very much to use the "is" attribute to customize built-in HTML elements but am worried about going down a dead end ? Hence the desire for usage stats. It seems like it's been in the W3C Spec for a while and is well supported in all modern browsers except Apple Webkit (Safari, Epiphany) at the time of writing.
https://html.spec.whatwg.org/multipage/custom-elements.html#attr-is
https://developer.mozilla.org/en-US/docs/Web/API/Web_components/Using_custom_elements
I am worried that the W3C, thanks to Apple's stance, may try to kill it off long term, despite the brilliant, working, Polyfill for the Apple Webkit Browser from @AndreaGiammarchi: https://github.com/ungap/custom-elements ?
eg:
<form is="my-custom-form" name="myForm"></form>
class MyCustomForm extends HTMLFormElement {
constructor() {
super();
}
connectedCallback() {
// Do stuff
}
}
// Define the custom element
customElements.define('my-custom-form', MyCustomForm, { extends: 'form' });
@Apple: If I can already do the following, then what's the big deal with security ?
document.forms.myForm.myCustomFunction=function(){ console.log('hello);}