Need help with javascript to show/hide all fields

I found this script in the forums and I was playing around with it and discovered it would hide all the fields but would not make them visible when I made the changes to visible. Here's the script:

var nButton = app.alert({

        cMsg: "Do you want to hide fields?",

        cTitle: "Make Read-Only?",

        nIcon: 2, nType: 2

    });

if (nButton == 4) {

    for (var i = 0; i < this.numFields; i++) {

        var fname = this.getNthFieldName(i);

        this.getField(fname).hidden = true; // makes all fields readonly

    }

}

this.getField("ButtonA").readonly = false;

this.getField("ButtonA").display = display.visible;

This script works to hide all fields but when I change "hidden" to "visible", and click the button, the fields remain hidden. I'd like to use something like this to hide/show the fields instead of using something like this to hide/show,

  this.getField("FieldA").display = display.hidden;

  this.getField("FieldA").display = display.visible;

(I have lots of fields to hide/show).

Can someone please show me how I can use the script above to hide and show my fields? I have two buttons, click button A to hide, click button B to make visible. I know this script above is to make the fields Read-Only but it also works to hide the fields so I thought it could also make the fields visible with a little modifying and expertise. Can someone let me know? Thank you guys.