Date field issue

I am not sure if it is only me. I have try this serveral times with date field component.

Here is my code:

		private function init():void
			text1.text = dateField.selectedDate.fullYear
			 + "/" + dateField.selectedDate.month + "/" +;

<mx:Text id="text1" />

<mx:DateField id="dateField" close="init();" formatString="YYYY/MM/DD"/>

after the date field closed, the text show the right YEAR and DATE, but not the right MONTH. If I choose January, the MONTH will actually becomes to ZERO.

Please, could anyone tell me why!

Thank you so much.

Have a good festive season.