var items = document.getItems({
		selected: true
})

var values = { 
		fills: true,
		strokes: false,
		swap: 'SWAP' 
}

var comps = {
		fills:{
				type: 'boolean',
				label: 'Fill -> Transparent'
		},

		strokes:{
				type: 'boolean',
				label: 'Strokes -> Transparent'
		},

		swap:{
				type: 'button',
				fullSize: true,
				onClick: function(){
						for(var i = 0; i < items.length; i++){
								var item = items[i]
								var tempStroke = item.strokeColor
								var tempFill = item.fillColor

								item.fillColor = comps.fills.value ? null : tempStroke
								item.strokeColor = comps.strokes.value ? null : tempFill
						}
				}
		}
}

var palette = new Palette('Swap Stroke/Fill', comps, values)