var sec = null;
var pageNum = null;

var re = /([-a-zA-Z]+)(\d+)?\.html$/;

defaultThumb = new Image(); defaultThumb.src = 'img/blank-thumb.gif';

myArray = re.exec(document.URL.toString());
if (myArray[1]) {
    sec = myArray[1];
}
if (myArray[2]) {
    pageNum = myArray[2];
}

if (sec == 'fire' || sec == 'joy' || sec == 'prints' || sec == 'color') {
    if (!pageNum) pageNum = 1;
}

function rollOn(imgName)
{
    document[imgName].src = eval(imgName + 'on.src');
    document.thumbnail.src = eval(imgName + 'thumb.src');
}

function rollOff(imgName)
{
    if (imgName != ('image' + pageNum)) document[imgName].src = eval(imgName + '.src');
    document.thumbnail.src = defaultThumb.src;
}