var wp_img_expanded = 'http://www.mailpound.com/blog/pics/up.png';
var wp_img_collapsed = 'http://www.mailpound.com/blog/pics/down.png';

// Cache the images upfront.
(new Image(15,15)).src = wp_img_expanded;
(new Image(15,15)).src = wp_img_collapsed;

function webpartExpand(htmlNode,imgNode) {
    if (document.getElementById && document.getElementById(htmlNode) != null) {
        document.getElementById(imgNode).src=wp_img_expanded;
        document.getElementById(htmlNode).className='webpartExpanded';
    }
}

function webpartCollapse(htmlNode,imgNode) {
    if (document.getElementById && document.getElementById(htmlNode) !=  null) {
        document.getElementById(imgNode).src=wp_img_collapsed;
        document.getElementById(htmlNode).className='webpartCollapsed';
    }
}

function webpartToggleExpansionStatus(nodeName) {
    htmlNode = nodeName + 'Panel';
    imgNode = nodeName + 'Image';

    if (document.getElementById && document.getElementById(htmlNode) !=  null) {
        nodeState = document.getElementById(htmlNode).className;
    }
    if (nodeState == 'webpartCollapsed') {
        webpartExpand(htmlNode,imgNode);
    }
    else {
        webpartCollapse(htmlNode,imgNode);
    }
    return false;
}