this is a local copy of certain logic from (Abstract)Element.getStyle to break a dependancy between the supports mechanism and Element use this instead of element references to check for styling info
function(element, styleName){
        var view = element.ownerDocument.defaultView,
            style = (view ? view.getComputedStyle(element, null) : element.currentStyle) || element.style;
        return style[styleName];
    }