Textformat.size < 10 is fault?

Hello~

I try it in html5 target
Discovery that tf.size = 3 , But result is fault!

	var txt:TextField = new TextField();	
	var tf:TextFormat = new TextFormat();
		tf.size = 3;
		tf.kerning = true;
		
		
		txt.defaultTextFormat = tf;
		txt.autoSize = TextFieldAutoSize.LEFT;
		
		txt.text = "OPENFL ";	


		addChild( txt );