Get Current FontSize

Hi,
I have a dynamic text box called artOne that I want to allow the user to decrease and increase the text size whenever they want. I can set up small, default and large options but I would prefer to have - & + buttons to decrease/increase the current font size by 2 points.
I know a bit of flash and understand using new TextFormat() like below


myLargeFormat = [COLOR=#000087]new[/COLOR] TextFormat();
myLargeFormat.[COLOR=#000087]font[/COLOR] = "[COLOR=blue]Arial[/COLOR]";
myLargeFormat.[COLOR=#000087]size[/COLOR] = 34;
myLargeFormat.[COLOR=#000087]color[/COLOR]=0xCCCCCC;
artOne.[COLOR=#000087]setTextFormat[/COLOR](myLargeFormat);

so I throught I could get the current font size


interval = 2;
tempSize = artOne.size;

then in the code above have the line


mytextFormat.[COLOR=#000087]size[/COLOR] = tempSize + interval;

but artOne.size returns no value so how would I get this value to use in the code.