#import 
#import 
#import 
typedef (CanvasRenderingContext2D or WebGLRenderingContext) RenderingContext;
interface HTMLCanvasElement : HTMLElement {
    RenderingContext? getContext(DOMString contextId, optional any options = null);
    attribute unsigned long width;
    attribute unsigned long height;
    USVString toDataURL(optional DOMString type = "image/png", optional double quality);
};