flutter web load html
import 'dart:ui' as ui;
import 'dart:html';
ui.platformViewRegistry.registerViewFactory(
'test-view-type',
(int viewId) => IFrameElement()
..width = '640'
..height = '360'
..src = "https://www.youtube.com/embed/5VbAwhBBHsg"
..style.border = 'none');
//just an example if you know how to code then change then feel free to change the values