var selectedFeature = 'feature1';
var fThumbArray = new Array('fThumb1','fThumb2','fThumb3','fThumb4');
var featureArray = new Array('feature1', 'feature2', 'feature3', 'feature4');

function selectThumb(whichFeature)
{
    for (i = 0; i < fThumbArray.length; i++)
    { 
        if (fThumbArray[i] == fThumbArray[whichFeature])
        {
            document.getElementById(fThumbArray[i]).style.backgroundImage = 'url(images/adblock/selected_feature.jpg)';
            document.getElementById(fThumbArray[i]).style.cursor = 'default';
            document.getElementById(fThumbArray[i]).style.color = '#411C0C';
        } 
        else 
        {
            document.getElementById(fThumbArray[i]).style.backgroundImage = 'none';
            document.getElementById(fThumbArray[i]).style.cursor = 'pointer';
            document.getElementById(fThumbArray[i]).style.color = '#666666';
        }
    }
    if (selectedFeature != featureArray[whichFeature])
    {
        document.getElementById(featureArray[whichFeature]).style.visibility = 'visible';
        Effect.Fade(selectedFeature); 
        Effect.Appear(featureArray[whichFeature]);
    }
    selectedFeature = featureArray[whichFeature];
}