Javascript – WebComponents – Expand an HTML element in Internet Explorer

I am trying to expand an element

through web components. This would be a very simple example of what I'm trying to do:

class CustomTable extends HTMLTableElement {

	constructor() {


		if (!this.hasAttribute('id'))
			this.setAttribute('id', 'NewCustomTableId');



customElements.define('custom-table', CustomTable, { extends: 'table' });

Column1 Column2
Row1 Column1 Row1 Col2
Row2 Col1 Row2 Col2

It works perfectly in other browsers, but I have problems in Internet Explorer. Finally, I did a little research and found that the attribute is HTML is not supported by IE or Safari.

As you can see from the code, I am currently using the following poly fill:

Does anyone know of a way to do this work?

Thanks in advance.