Changing dynamic text field value via button

Hi all

I’m just doing a test for the moment, where iv’e got a dynamic text field and a button. All i want is when the user presses the button, the numerical value of the number displayed in the text field increases by 1.

ActionScript Code:
[LEFT]but.[COLOR=#993300]onRelease[/COLOR] = [COLOR=#993300]function[/COLOR][COLOR=#000000]([/COLOR][COLOR=#000000])[/COLOR] [COLOR=#000000]{[/COLOR]

[COLOR=#993300]var[/COLOR] testvar = testvar+[COLOR=#000000]1[/COLOR];

[COLOR=#000000]}[/COLOR];
[/LEFT]

Yeah, i’m a newbie, and of course the above code dosen’t work. Any pointers to get this to succeed?

Many thanks