flex - mx:HTML control won't display when added in code-behind -

i building air application , planning include mx:html control can't seem control display. here code:

var tmphtml:html = new html(); tmphtml.htmltext = "<a>this sample </a>"; tmphtml.x = 48; tmphtml.y = 10; tmphtml.width = 360; tmphtml.height = 169; tmphtml.visible = true; stage.addchild(tmphtml); stage.scalemode = stagescalemode.no_scale; stage.addchild(txt); 

you need add tmphtml application, not stage.