jQuery mapster and tooltip

I have the following jQuery script that displays a tooltip over a map area on hover.  I would like to display different classes depending upon the area that is hovered.

How do I change the class here in the jQuey;

<script>
<script type='text/javascript'>
$(window).load(function(){
var image = $('#mapping');
var oklahoma = 'Oklahoma';
var bakken = 'Bakken';
var niobara = 'Niobara';
var permian = 'Permian';
var eagleford = 'Eagle Ford';
$('img').mapster({
            fill: true,
            fillColor: 'ffffff',
            fillColorMask: 'FFFFFF',
            fillOpacity: 0,
            strokeOpacity: 1,
            strokeWidth: 1,
            isSelectable: false,
            singleSelect: true,
            mapKey: 'name',
            listKey: 'name',
            toolTipContainer: '<div class="map-bubble map-bubble-font"> </div>', 
            showToolTip: true,
            toolTipClose: ["area-mouseout"],
            areas: [{
        		key: "oklahoma",
        		toolTip: oklahoma
        	},
        	{
        		key: "bakken",
        		toolTip: bakken
        	},
        	{
        		key: "niobara",
        		toolTip: niobara
        	},
        	{
        		key: "permian",
        		toolTip: permian
        	},
        	{
        		key: "eagleford",
        		toolTip: eagleford
        	}
        	
        	]
        })
});
</script>

</script>

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