How to achieve conditional formatting in PDF

Hello, I tried to set up some conditional formating on a PDF form and am hot sure where it went wrong. Here's what I hoped to achieve: I configured three check-box field "Check Box5.0.0.0", "Check Box5.1.0", and "Check Box5.2.0.0", and I want the three box to be filled with green, red, and purple if they're checked individually.

I confugured them to run a Javascript, with Mouth Up as the trigger, and the code is below:

if(event.target.value != "Off")

    this.getField("Check Box5.0.0.0").fillColor = color.yellow;

else

    this.getField("Check Box5.0.0.0").fillColor = color.transparent; 

I edited the form on MacOS and it seems to be working, but when I later open it up on a PC, it behaves really strange. Same thing happened when I opened it on a differnet Mac. Once I checked another box, it'll clear up the color for the previous check-box. Not sure where I got it wrong. Thanks!