how to change the border to none using javascript?

Hi

guys im pretty new to adobe live cycle designer es2 i have a really easy one.

how do i change the boxtype or apperance of a textbox  from solid to none after pressing a button

I have tried this on the click even tof a a button but does not seem to work.

NumericField1[0].border = "None";   

any suggestions? would be greatly appreciated it from a youn noob.