function css(obj, attr, value)
{
    if(arguments.length==2)
        return parseFloat(obj.currentStyle?obj.currentStyle[attr]:document.defaultView.getComputedStyle(obj, false)[attr]);
    else if(arguments.length==3)
        switch(attr)
        {
            case 'width':
            case 'height':
            case 'paddingLeft':
            case 'paddingTop':
            case 'paddingRight':
            case 'paddingBottom':
                value=Math.max(value,0);
            case 'left':
            case 'top':
            case 'marginLeft':
            case 'marginTop':
            case 'marginRight':
            case 'marginBottom':
                obj.style[attr]=value+'px';
                break;
            case 'opacity':
                obj.style.filter="alpha(opacity:"+value*100+")";
                obj.style.opacity=value;
                break;
            default:
                obj.style[attr]=value;
        }
    
    return function (attr_in, value_in){css(obj, attr_in, value_in)};
}